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..5f493b94e 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 +1,10 @@
 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.SelectOne
+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 +37,28 @@ 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 ssn = Text("Social Security Number" )
+        val customText = ParticipantAttribute.CustomParticipantAttribute( ssn )
+        protocol.addExpectedParticipantData( ExpectedParticipantData( customText ) )
+
+        val os = SelectOne( "Favorite OS", setOf( "Windows", "Linux", "Mac" ) )
+        val customSelectOne = ParticipantAttribute.CustomParticipantAttribute( os )
+        protocol.addExpectedParticipantData( ExpectedParticipantData( customSelectOne ) )
+
+        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..a60d0cddf
--- /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 +1,109 @@
+[
+    {
+        "outcome": "Succeeded",
+        "request": {
+            "__type": "dk.cachet.carp.protocols.infrastructure.ProtocolServiceRequest.Add",
+            "apiVersion": "1.1",
+            "protocol": {
+                "id": "0d57f923-955e-4693-a606-cca9651aab4a",
+                "createdOn": "2023-12-10T18:51:39.511538600Z",
+                "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.a1eda4bcd0d84ca0ba446cabfa4e84c8"
+                        }
+                    },
+                    {
+                        "attribute": {
+                            "__type": "dk.cachet.carp.common.application.users.ParticipantAttribute.CustomParticipantAttribute",
+                            "input": {
+                                "__type": "dk.cachet.carp.common.application.data.input.elements.SelectOne",
+                                "prompt": "Favorite OS",
+                                "options": [
+                                    "Windows",
+                                    "Linux",
+                                    "Mac"
+                                ]
+                            },
+                            "inputDataType": "dk.cachet.carp.input.custom.4ee5a0cc0ce5462b94baee4e59415f9b"
+                        }
+                    }
+                ]
+            }
+        },
+        "precedingEvents": [
+        ],
+        "publishedEvents": [
+        ],
+        "response": {
+        }
+    },
+    {
+        "outcome": "Succeeded",
+        "request": {
+            "__type": "dk.cachet.carp.protocols.infrastructure.ProtocolServiceRequest.GetBy",
+            "apiVersion": "1.1",
+            "protocolId": "0d57f923-955e-4693-a606-cca9651aab4a"
+        },
+        "precedingEvents": [
+        ],
+        "publishedEvents": [
+        ],
+        "response": {
+            "id": "0d57f923-955e-4693-a606-cca9651aab4a",
+            "createdOn": "2023-12-10T18:51:39.511538600Z",
+            "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.a1eda4bcd0d84ca0ba446cabfa4e84c8"
+                    }
+                },
+                {
+                    "attribute": {
+                        "__type": "dk.cachet.carp.common.application.users.ParticipantAttribute.CustomParticipantAttribute",
+                        "input": {
+                            "__type": "dk.cachet.carp.common.application.data.input.elements.SelectOne",
+                            "prompt": "Favorite OS",
+                            "options": [
+                                "Windows",
+                                "Linux",
+                                "Mac"
+                            ]
+                        },
+                        "inputDataType": "dk.cachet.carp.input.custom.4ee5a0cc0ce5462b94baee4e59415f9b"
+                    }
+                }
+            ]
+        }
+    }
+]
\ No newline at end of file