diff --git a/src/main/scala/it/pagopa/interop/catalogprocess/api/impl/ProcessApiServiceImpl.scala b/src/main/scala/it/pagopa/interop/catalogprocess/api/impl/ProcessApiServiceImpl.scala
index 81898e90..61076bea 100644
--- a/src/main/scala/it/pagopa/interop/catalogprocess/api/impl/ProcessApiServiceImpl.scala
+++ b/src/main/scala/it/pagopa/interop/catalogprocess/api/impl/ProcessApiServiceImpl.scala
@@ -358,6 +358,9 @@ final case class ProcessApiServiceImpl(
       catalogItem    <- catalogManagementService.getEServiceById(eServiceUuid)
       _              <- assertRequesterAllowed(catalogItem.producerId)(organizationId)
       descriptor     <- assertDescriptorExists(catalogItem, descriptorUuid)
+      _              <-
+        if (documentSeed.kind == EServiceDocumentKind.INTERFACE) assertInterfaceDoesNotExists(descriptor)
+        else Future.unit
       updated        <- catalogManagementService.createEServiceDocument(catalogItem.id, descriptor.id, managementSeed)
     } yield updated.toApi
 
@@ -859,4 +862,9 @@ object ProcessApiServiceImpl {
       .find(_.id == descriptorId)
       .toFuture(EServiceDescriptorNotFound(eService.id.toString, descriptorId.toString))
 
+  def assertInterfaceDoesNotExists(descriptor: CatalogDescriptor): Future[Unit] =
+    descriptor.interface match {
+      case Some(_) => Future.failed(InterfaceAlreadyExists(descriptor.id))
+      case None    => Future.unit
+    }
 }
diff --git a/src/main/scala/it/pagopa/interop/catalogprocess/api/impl/ResponseHandlers.scala b/src/main/scala/it/pagopa/interop/catalogprocess/api/impl/ResponseHandlers.scala
index cd1144b5..3f8d9e9b 100644
--- a/src/main/scala/it/pagopa/interop/catalogprocess/api/impl/ResponseHandlers.scala
+++ b/src/main/scala/it/pagopa/interop/catalogprocess/api/impl/ResponseHandlers.scala
@@ -200,6 +200,7 @@ object ResponseHandlers extends AkkaResponses {
     result match {
       case Success(s)                              => success(s)
       case Failure(ex: OperationForbidden.type)    => forbidden(ex, logMessage)
+      case Failure(ex: InterfaceAlreadyExists)     => badRequest(ex, logMessage)
       case Failure(ex: EServiceNotFound)           => notFound(ex, logMessage)
       case Failure(ex: EServiceDescriptorNotFound) => notFound(ex, logMessage)
       case Failure(ex)                             => internalServerError(ex, logMessage)
diff --git a/src/main/scala/it/pagopa/interop/catalogprocess/errors/CatalogProcessErrors.scala b/src/main/scala/it/pagopa/interop/catalogprocess/errors/CatalogProcessErrors.scala
index 3025293d..484ce0db 100644
--- a/src/main/scala/it/pagopa/interop/catalogprocess/errors/CatalogProcessErrors.scala
+++ b/src/main/scala/it/pagopa/interop/catalogprocess/errors/CatalogProcessErrors.scala
@@ -76,4 +76,7 @@ object CatalogProcessErrors {
   final case class AttributeNotFound(attributeId: UUID)
       extends ComponentError("0020", s"Attribute ${attributeId.toString} not found")
 
+  final case class InterfaceAlreadyExists(descriptorId: UUID)
+      extends ComponentError("0021", s"Descriptor ${descriptorId.toString} already has an interface")
+
 }
diff --git a/src/test/scala/it/pagopa/interop/catalogprocess/CatalogProcessSpec.scala b/src/test/scala/it/pagopa/interop/catalogprocess/CatalogProcessSpec.scala
index 70e77c8d..494531d0 100644
--- a/src/test/scala/it/pagopa/interop/catalogprocess/CatalogProcessSpec.scala
+++ b/src/test/scala/it/pagopa/interop/catalogprocess/CatalogProcessSpec.scala
@@ -2489,6 +2489,52 @@ class CatalogProcessSpec extends SpecHelper with AnyWordSpecLike with ScalatestR
         status shouldEqual StatusCodes.Forbidden
       }
     }
+    "fail if document is an interface and it already exists" in {
+      val requesterId                             = UUID.randomUUID()
+      val descriptorId                            = UUID.randomUUID()
+      implicit val context: Seq[(String, String)] =
+        Seq("bearer" -> bearerToken, USER_ROLES -> "admin", ORGANIZATION_ID_CLAIM -> requesterId.toString)
+
+      val descriptor = SpecData.catalogDescriptor.copy(
+        id = descriptorId,
+        interface = Some(
+          CatalogDocument(
+            id = UUID.randomUUID(),
+            name = "name",
+            contentType = "application/yaml",
+            prettyName = "pretty",
+            path = "path",
+            checksum = "checksum",
+            uploadDate = OffsetDateTimeSupplier.get().minusDays(10)
+          )
+        )
+      )
+
+      val eService = SpecData.catalogItem.copy(descriptors = Seq(descriptor), producerId = requesterId)
+
+      val documentId = UUID.randomUUID()
+
+      val seed = CreateEServiceDescriptorDocumentSeed(
+        documentId = documentId,
+        kind = EServiceDocumentKind.INTERFACE,
+        prettyName = "prettyName",
+        filePath = "filePath",
+        fileName = "fileName",
+        contentType = "application/json",
+        checksum = "checksum",
+        serverUrls = Seq.empty
+      )
+
+      (mockCatalogManagementService
+        .getEServiceById(_: UUID)(_: ExecutionContext, _: ReadModelService))
+        .expects(SpecData.catalogItem.id, *, *)
+        .once()
+        .returns(Future.successful(eService))
+
+      Post() ~> service.createEServiceDocument(SpecData.catalogItem.id.toString, descriptorId.toString, seed) ~> check {
+        status shouldEqual StatusCodes.BadRequest
+      }
+    }
   }
   "Document retrieve" should {
     "succeed" in {