diff --git a/src/Radarr.Api.V3/ImportLists/ImportListExclusionController.cs b/src/Radarr.Api.V3/ImportLists/ImportListExclusionController.cs
index 976b537e4..f1ca38b6e 100644
--- a/src/Radarr.Api.V3/ImportLists/ImportListExclusionController.cs
+++ b/src/Radarr.Api.V3/ImportLists/ImportListExclusionController.cs
@@ -16,11 +16,15 @@ namespace Radarr.Api.V3.ImportLists
     {
         private readonly IImportListExclusionService _importListExclusionService;
 
-        public ImportListExclusionController(IImportListExclusionService importListExclusionService)
+        public ImportListExclusionController(IImportListExclusionService importListExclusionService,
+                                             ImportListExclusionExistsValidator importListExclusionExistsValidator)
         {
             _importListExclusionService = importListExclusionService;
 
-            SharedValidator.RuleFor(c => c.TmdbId).GreaterThan(0);
+            SharedValidator.RuleFor(c => c.TmdbId).Cascade(CascadeMode.Stop)
+                .NotEmpty()
+                .SetValidator(importListExclusionExistsValidator);
+
             SharedValidator.RuleFor(c => c.MovieTitle).NotEmpty();
             SharedValidator.RuleFor(c => c.MovieYear).GreaterThan(0);
         }
diff --git a/src/Radarr.Api.V3/ImportLists/ImportListExclusionExistsValidator.cs b/src/Radarr.Api.V3/ImportLists/ImportListExclusionExistsValidator.cs
new file mode 100644
index 000000000..bb27c80c4
--- /dev/null
+++ b/src/Radarr.Api.V3/ImportLists/ImportListExclusionExistsValidator.cs
@@ -0,0 +1,32 @@
+using FluentValidation.Validators;
+using NzbDrone.Core.ImportLists.ImportExclusions;
+
+namespace Radarr.Api.V3.ImportLists
+{
+    public class ImportListExclusionExistsValidator : PropertyValidator
+    {
+        private readonly IImportListExclusionService _importListExclusionService;
+
+        public ImportListExclusionExistsValidator(IImportListExclusionService importListExclusionService)
+        {
+            _importListExclusionService = importListExclusionService;
+        }
+
+        protected override string GetDefaultMessageTemplate() => "This exclusion has already been added.";
+
+        protected override bool IsValid(PropertyValidatorContext context)
+        {
+            if (context.PropertyValue == null)
+            {
+                return true;
+            }
+
+            if (context.InstanceToValidate is not ImportListExclusionResource listExclusionResource)
+            {
+                return true;
+            }
+
+            return !_importListExclusionService.All().Exists(v => v.TmdbId == (int)context.PropertyValue && v.Id != listExclusionResource.Id);
+        }
+    }
+}