diff --git a/carp.protocols.core/src/commonTest/kotlin/dk/cachet/carp/protocols/application/ProtocolServiceTest.kt b/carp.protocols.core/src/commonTest/kotlin/dk/cachet/carp/protocols/application/ProtocolServiceTest.kt
index e8d7812e3..6734c2759 100644
--- a/carp.protocols.core/src/commonTest/kotlin/dk/cachet/carp/protocols/application/ProtocolServiceTest.kt
+++ b/carp.protocols.core/src/commonTest/kotlin/dk/cachet/carp/protocols/application/ProtocolServiceTest.kt
@@ -1,7 +1,9 @@
 package dk.cachet.carp.protocols.application
 
 import dk.cachet.carp.common.application.UUID
+import dk.cachet.carp.common.application.data.input.CarpInputDataTypes
 import dk.cachet.carp.common.application.data.input.InputDataType
+import dk.cachet.carp.common.application.data.input.elements.Text
 import dk.cachet.carp.common.application.triggers.TaskControl
 import dk.cachet.carp.common.application.users.ExpectedParticipantData
 import dk.cachet.carp.common.application.users.ParticipantAttribute
@@ -34,6 +36,22 @@ interface ProtocolServiceTest
         assertEquals( snapshot, retrieved )
     }
 
+    @Test
+    fun add_protocol_with_expected_participant_data_succeeds() = runTest {
+        val service = createService()
+        val protocol = createEmptyProtocol()
+
+        val sex = ParticipantAttribute.DefaultParticipantAttribute(CarpInputDataTypes.SEX)
+        protocol.addExpectedParticipantData(ExpectedParticipantData(sex))
+        val customInput = ParticipantAttribute.CustomParticipantAttribute(Text("Social Security Number"))
+        protocol.addExpectedParticipantData(ExpectedParticipantData(customInput))
+        val snapshot = protocol.getSnapshot()
+
+        service.add( snapshot )
+        val retrieved = service.getBy( protocol.id )
+        assertEquals( snapshot, retrieved )
+    }
+
     @Test
     fun add_fails_when_protocol_already_exists() = runTest {
         val service = createService()
diff --git a/carp.protocols.core/src/commonTest/resources/test-requests/ProtocolService/1.1/ProtocolServiceTest/add_protocol_with_expected_participant_data_succeeds.json b/carp.protocols.core/src/commonTest/resources/test-requests/ProtocolService/1.1/ProtocolServiceTest/add_protocol_with_expected_participant_data_succeeds.json
new file mode 100644
index 000000000..23c98b2f0
--- /dev/null
+++ b/carp.protocols.core/src/commonTest/resources/test-requests/ProtocolService/1.1/ProtocolServiceTest/add_protocol_with_expected_participant_data_succeeds.json
@@ -0,0 +1,79 @@
+[
+    {
+        "outcome": "Succeeded",
+        "request": {
+            "__type": "dk.cachet.carp.protocols.infrastructure.ProtocolServiceRequest.Add",
+            "apiVersion": "1.1",
+            "protocol": {
+                "id": "b2e7a95f-1cf2-4f25-9671-d3cd5eeaae1c",
+                "createdOn": "2023-12-10T18:30:52.775778700Z",
+                "version": 0,
+                "ownerId": "27879e75-ccc1-4866-9ab3-4ece1b735052",
+                "name": "Test protocol",
+                "description": "Test description",
+                "expectedParticipantData": [
+                    {
+                        "attribute": {
+                            "__type": "dk.cachet.carp.common.application.users.ParticipantAttribute.DefaultParticipantAttribute",
+                            "inputDataType": "dk.cachet.carp.input.sex"
+                        }
+                    },
+                    {
+                        "attribute": {
+                            "__type": "dk.cachet.carp.common.application.users.ParticipantAttribute.CustomParticipantAttribute",
+                            "input": {
+                                "__type": "dk.cachet.carp.common.application.data.input.elements.Text",
+                                "prompt": "Social Security Number"
+                            },
+                            "inputDataType": "dk.cachet.carp.input.custom.6dc4b930d73c45cd8c7017f9fd823fe6"
+                        }
+                    }
+                ]
+            }
+        },
+        "precedingEvents": [
+        ],
+        "publishedEvents": [
+        ],
+        "response": {
+        }
+    },
+    {
+        "outcome": "Succeeded",
+        "request": {
+            "__type": "dk.cachet.carp.protocols.infrastructure.ProtocolServiceRequest.GetBy",
+            "apiVersion": "1.1",
+            "protocolId": "b2e7a95f-1cf2-4f25-9671-d3cd5eeaae1c"
+        },
+        "precedingEvents": [
+        ],
+        "publishedEvents": [
+        ],
+        "response": {
+            "id": "b2e7a95f-1cf2-4f25-9671-d3cd5eeaae1c",
+            "createdOn": "2023-12-10T18:30:52.775778700Z",
+            "version": 0,
+            "ownerId": "27879e75-ccc1-4866-9ab3-4ece1b735052",
+            "name": "Test protocol",
+            "description": "Test description",
+            "expectedParticipantData": [
+                {
+                    "attribute": {
+                        "__type": "dk.cachet.carp.common.application.users.ParticipantAttribute.DefaultParticipantAttribute",
+                        "inputDataType": "dk.cachet.carp.input.sex"
+                    }
+                },
+                {
+                    "attribute": {
+                        "__type": "dk.cachet.carp.common.application.users.ParticipantAttribute.CustomParticipantAttribute",
+                        "input": {
+                            "__type": "dk.cachet.carp.common.application.data.input.elements.Text",
+                            "prompt": "Social Security Number"
+                        },
+                        "inputDataType": "dk.cachet.carp.input.custom.6dc4b930d73c45cd8c7017f9fd823fe6"
+                    }
+                }
+            ]
+        }
+    }
+]
\ No newline at end of file