diff --git a/backend/app/api/v1/endpoints/tickets.py b/backend/app/api/v1/endpoints/tickets.py
index ae2e522..adedbef 100644
--- a/backend/app/api/v1/endpoints/tickets.py
+++ b/backend/app/api/v1/endpoints/tickets.py
@@ -589,7 +589,6 @@ async def get_ticket_issues(
 async def create_ticket_issue(
     ticket_id: str,
     issue: IssueCreate,
-    file: Optional[UploadFile] = File(None),
     db: AsyncSession = Depends(get_db),
     current_user: User = Depends(get_current_user),
     current_tenant: Tenant = Depends(get_current_tenant),
@@ -633,21 +632,11 @@ async def create_ticket_issue(
                 detail=f"Usuarios no encontrados: {missing}",
             )
 
-    attachment_path = None
-    attachment_filename = None
-    attachment_mime_type = None
-    if file and file.filename:
-        file_metadata = await file_handler.save_upload(file, current_tenant.id, ticket_uuid)
-        attachment_path = file_metadata["file_path"]
-        attachment_filename = file_metadata["original_filename"]
-        attachment_mime_type = file_metadata["mime_type"]
-
     new_issue = TicketIssue(
         id=uuid.uuid4(), ticket_id=ticket_uuid,
-        tenant_id=current_user.tenant_id, created_by=current_user.id,
+        tenant_id=ticket_obj.tenant_id, created_by=current_user.id,
         content=issue.content, priority=TicketPriority[issue.priority],
-        attachment_path=attachment_path, attachment_filename=attachment_filename,
-        attachment_mime_type=attachment_mime_type,
+        attachment_path=None, attachment_filename=None, attachment_mime_type=None,
         created_at=datetime.utcnow(), updated_at=datetime.utcnow(),
     )
     new_issue.tagged_users = tagged_users
@@ -677,4 +666,47 @@ async def create_ticket_issue(
         attachment_filename=new_issue.attachment_filename,
         attachment_mime_type=new_issue.attachment_mime_type,
         created_at=new_issue.created_at, updated_at=new_issue.updated_at,
-    )
\ No newline at end of file
+    )
+
+
+@router.post("/{ticket_id}/issues/{issue_id}/attachment", status_code=status.HTTP_200_OK)
+async def upload_issue_attachment(
+    ticket_id: str,
+    issue_id: str,
+    file: UploadFile = File(...),
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+    current_tenant: Tenant = Depends(get_current_tenant),
+):
+    """Subir adjunto a un asunto existente."""
+    ticket_uuid = validate_uuid_param(ticket_id, "ticket ID")
+    issue_uuid = validate_uuid_param(issue_id, "issue ID")
+
+    result = await db.execute(
+        select(TicketIssue).where(
+            TicketIssue.id == issue_uuid,
+            TicketIssue.ticket_id == ticket_uuid,
+        )
+    )
+    db_issue = result.scalars().first()
+    if not db_issue:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Asunto no encontrado")
+
+    if db_issue.created_by != current_user.id and not current_user.role.is_global:
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Sin permisos")
+
+    upload_tenant_id = db_issue.tenant_id
+    file_metadata = await file_handler.save_upload(file, upload_tenant_id, ticket_uuid)
+
+    db_issue.attachment_path = file_metadata["file_path"]
+    db_issue.attachment_filename = file_metadata["original_filename"]
+    db_issue.attachment_mime_type = file_metadata["mime_type"]
+    db_issue.updated_at = datetime.utcnow()
+
+    await db.commit()
+
+    return {
+        "message": "Adjunto subido correctamente",
+        "attachment_filename": db_issue.attachment_filename,
+        "attachment_mime_type": db_issue.attachment_mime_type,
+    }
\ No newline at end of file
diff --git a/frontend-internal/src/lib/components/IssueModal.svelte b/frontend-internal/src/lib/components/IssueModal.svelte
index a371ebc..068ff80 100644
--- a/frontend-internal/src/lib/components/IssueModal.svelte
+++ b/frontend-internal/src/lib/components/IssueModal.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
-  import { createEventDispatcher } from 'svelte';
-  import { api } from '$lib/utils/api';
   import { toast } from '$lib/stores/toast';
+  import { api } from '$lib/utils/api';
+  import { createEventDispatcher } from 'svelte';
 
   export let ticketId: string;
   export let users: any[] = [];
@@ -43,20 +43,18 @@
 
     isSubmitting = true;
     try {
-      // Si hay archivo usamos FormData, si no JSON normal
+      // 1. Crear el issue con JSON
+      const newIssue = await api.post(`/tickets/${ticketId}/issues`, {
+        content: content.trim(),
+        priority,
+        tagged_user_ids: taggedUserIds
+      });
+
+      // 2. Si hay archivo, subirlo en request separado
       if (file) {
         const formData = new FormData();
-        formData.append('content', content.trim());
-        formData.append('priority', priority);
-        taggedUserIds.forEach(id => formData.append('tagged_user_ids', id));
         formData.append('file', file);
-        await api.postForm(`/tickets/${ticketId}/issues`, formData);
-      } else {
-        await api.post(`/tickets/${ticketId}/issues`, {
-          content: content.trim(),
-          priority,
-          tagged_user_ids: taggedUserIds
-        });
+        await api.postForm(`/tickets/${ticketId}/issues/${newIssue.id}/attachment`, formData);
       }
 
       toast.success('Asunto creado correctamente');
@@ -83,7 +81,7 @@
       on:click={handleClose}
       role="button"
       tabindex="-1"
-      on:keydown={(e) => e.key === 'Escape' && handleClose()}
+      on:keydown={e => e.key === 'Escape' && handleClose()}
     />
 
     <!-- Modal -->
@@ -91,21 +89,21 @@
       <!-- Header -->
       <div class="flex items-center justify-between px-6 py-4 border-b border-gray-200">
         <h3 class="text-lg font-semibold text-gray-900">Crear Asunto</h3>
-        <button
-          type="button"
-          on:click={handleClose}
-          class="text-gray-400 hover:text-gray-500"
-        >
+        <button type="button" on:click={handleClose} class="text-gray-400 hover:text-gray-500">
           <span class="sr-only">Cerrar</span>
           <svg class="h-5 w-5" fill="none" viewBox="0 0 24 24" stroke="currentColor">
-            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M6 18L18 6M6 6l12 12" />
+            <path
+              stroke-linecap="round"
+              stroke-linejoin="round"
+              stroke-width="2"
+              d="M6 18L18 6M6 6l12 12"
+            />
           </svg>
         </button>
       </div>
 
       <!-- Body -->
       <div class="px-6 py-5 space-y-5">
-
         <!-- Contenido -->
         <div>
           <label class="block text-sm font-medium text-gray-700 mb-1">
@@ -141,10 +139,10 @@
         <!-- Usuarios a etiquetar -->
         {#if users.length > 0}
           <div>
-            <label class="block text-sm font-medium text-gray-700 mb-2">
-              Etiquetar usuarios
-            </label>
-            <div class="max-h-40 overflow-y-auto border border-gray-200 rounded-md divide-y divide-gray-100">
+            <label class="block text-sm font-medium text-gray-700 mb-2"> Etiquetar usuarios </label>
+            <div
+              class="max-h-40 overflow-y-auto border border-gray-200 rounded-md divide-y divide-gray-100"
+            >
               {#each users as user}
                 <label class="flex items-center gap-3 px-3 py-2 hover:bg-gray-50 cursor-pointer">
                   <input
@@ -157,7 +155,8 @@
                   />
                   <div class="flex flex-col">
                     <span class="text-sm font-medium text-gray-900">
-                      {user.first_name} {user.last_name}
+                      {user.first_name}
+                      {user.last_name}
                     </span>
                     <span class="text-xs text-gray-500">{user.email}</span>
                   </div>
@@ -166,7 +165,10 @@
             </div>
             {#if taggedUserIds.length > 0}
               <p class="text-xs text-blue-600 mt-1">
-                {taggedUserIds.length} usuario{taggedUserIds.length > 1 ? 's' : ''} seleccionado{taggedUserIds.length > 1 ? 's' : ''}
+                {taggedUserIds.length} usuario{taggedUserIds.length > 1 ? 's' : ''} seleccionado{taggedUserIds.length >
+                1
+                  ? 's'
+                  : ''}
               </p>
             {/if}
           </div>
@@ -174,9 +176,7 @@
 
         <!-- Adjunto -->
         <div>
-          <label class="block text-sm font-medium text-gray-700 mb-1">
-            Adjunto (opcional)
-          </label>
+          <label class="block text-sm font-medium text-gray-700 mb-1"> Adjunto (opcional) </label>
           <input
             bind:this={fileInput}
             type="file"
@@ -227,4 +227,4 @@
       </div>
     </div>
   </div>
-</div>
\ No newline at end of file
+</div>
diff --git a/frontend-internal/src/routes/tickets/[id]/+page.svelte b/frontend-internal/src/routes/tickets/[id]/+page.svelte
index 5243986..40b3031 100644
--- a/frontend-internal/src/routes/tickets/[id]/+page.svelte
+++ b/frontend-internal/src/routes/tickets/[id]/+page.svelte
@@ -73,9 +73,11 @@
 
     isSubmittingComment = true;
     try {
-      const comment = await api.post(`/tickets/${ticketId}/comments`, {
-        content: newComment.trim(),
-        is_internal: false
+      const comment = await api.post(`/tickets/${ticketId}/issues`, {
+              content: content.trim(),
+              priority,
+              tagged_user_ids: taggedUserIds
+
       });
       comments = [...comments, comment];
       newComment = '';