diff --git a/lib/services/entity-sync.ts b/lib/services/entity-sync.ts
index 1103cb6..bb57f3b 100644
--- a/lib/services/entity-sync.ts
+++ b/lib/services/entity-sync.ts
@@ -10,18 +10,19 @@ import { EntityType } from '../types/sync';
 import { mapAutotaskToDatabase, mapAutotaskBatch } from '../utils/entity-mapper';
 import { bulkUpsertRecords, getLastSyncTime, softDeleteMissingRecords } from '../utils/db-helpers';
 import { syncProgressTracker } from './sync-progress-tracker';
-import { 
-  getAutotaskEntityName, 
+import {
+  getAutotaskEntityName,
   buildIncrementalFilter,
   buildActiveFilter,
   buildDateRangeFilter,
+  buildCompaniesFilter,
   buildContractsFilter,
   buildContractServicesFilter,
   buildProjectsFilter,
   buildProjectPhasesFilter,
   buildTimeEntriesFilter,
   buildBillingItemsFilter,
-  getTableName 
+  getTableName
 } from '../utils/sync-helpers';
 import { createSyncLogger, SyncPhase, categorizeError } from '../utils/sync-logger';
 
@@ -128,9 +129,12 @@ export class EntitySyncService {
         }
         
         const filters: Array<{ field: string; op: string; value: any }> = [];
-        
+
         // Special handling for entities that require filters
-        if (entity === EntityType.CONTRACTS) {
+        if (entity === EntityType.COMPANIES) {
+          filters.push(...buildCompaniesFilter());
+          entityLogger.info('Full sync of all companies (active + inactive)');
+        } else if (entity === EntityType.CONTRACTS) {
           filters.push(...buildContractsFilter());
           entityLogger.info('Full sync with status filter for active contracts');
         } else if (entity === EntityType.CONTRACT_SERVICES) {
diff --git a/lib/utils/sync-helpers.ts b/lib/utils/sync-helpers.ts
index 25274d9..0d0b836 100644
--- a/lib/utils/sync-helpers.ts
+++ b/lib/utils/sync-helpers.ts
@@ -91,6 +91,22 @@ export function buildContractServicesFilter(): Array<{ field: string; op: string
   ];
 }
 
+/**
+ * Build filter for companies (Companies endpoint requires a filter — use id > 0 to fetch all
+ * companies regardless of isActive. Active-only filtering misses inactive companies that
+ * have tickets, causing tickets_company_id_fkey violations on full sync.)
+ * @returns Query filter array for all companies
+ */
+export function buildCompaniesFilter(): Array<{ field: string; op: string; value: any }> {
+  return [
+    {
+      field: 'id',
+      op: 'gt',
+      value: 0,
+    },
+  ];
+}
+
 /**
  * Get table name for entity type
  * @param entity Entity type