diff --git a/src/main/java/org/hostsharing/hsadminng/domain/Membership.java b/src/main/java/org/hostsharing/hsadminng/domain/Membership.java
index c3e15d50..6c6e87e0 100644
--- a/src/main/java/org/hostsharing/hsadminng/domain/Membership.java
+++ b/src/main/java/org/hostsharing/hsadminng/domain/Membership.java
@@ -1,17 +1,15 @@
 package org.hostsharing.hsadminng.domain;
 
 
-import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 
 import javax.persistence.*;
-import javax.validation.constraints.*;
-
+import javax.validation.constraints.NotNull;
 import java.io.Serializable;
 import java.time.LocalDate;
 import java.util.HashSet;
-import java.util.Set;
 import java.util.Objects;
+import java.util.Set;
 
 /**
  * A Membership.
@@ -21,7 +19,9 @@ import java.util.Objects;
 public class Membership implements Serializable {
 
     private static final long serialVersionUID = 1L;
-    
+
+    public static final String ENTITY_NAME = "membership";
+
     @Id
     @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequenceGenerator")
     @SequenceGenerator(name = "sequenceGenerator")
diff --git a/src/main/java/org/hostsharing/hsadminng/service/MembershipService.java b/src/main/java/org/hostsharing/hsadminng/service/MembershipService.java
index 53fb74cb..c0804e2b 100644
--- a/src/main/java/org/hostsharing/hsadminng/service/MembershipService.java
+++ b/src/main/java/org/hostsharing/hsadminng/service/MembershipService.java
@@ -4,9 +4,9 @@ import org.hostsharing.hsadminng.domain.Membership;
 import org.hostsharing.hsadminng.repository.MembershipRepository;
 import org.hostsharing.hsadminng.service.dto.MembershipDTO;
 import org.hostsharing.hsadminng.service.mapper.MembershipMapper;
+import org.hostsharing.hsadminng.web.rest.errors.BadRequestAlertException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
@@ -73,12 +73,12 @@ public class MembershipService {
     }
 
     /**
-     * Delete the membership by id.
+     * Prevent deleting a membership by id via service call.
      *
      * @param id the id of the entity
      */
     public void delete(Long id) {
         log.debug("Request to delete Membership : {}", id);
-        membershipRepository.deleteById(id);
+        throw new BadRequestAlertException("Membership cannot be deleted", Membership.ENTITY_NAME, "membershipNotDeletable");
     }
 }
diff --git a/src/main/java/org/hostsharing/hsadminng/service/ShareService.java b/src/main/java/org/hostsharing/hsadminng/service/ShareService.java
index c7627c58..76552c01 100644
--- a/src/main/java/org/hostsharing/hsadminng/service/ShareService.java
+++ b/src/main/java/org/hostsharing/hsadminng/service/ShareService.java
@@ -85,7 +85,7 @@ public class ShareService {
     }
 
     /**
-     * Delete the share by id.
+     * Prevent deleting a share transaction by id via service call
      *
      * @param id the id of the entity
      */
diff --git a/src/main/webapp/i18n/de/custom-error.json b/src/main/webapp/i18n/de/custom-error.json
index 9eef28b4..4c87053e 100644
--- a/src/main/webapp/i18n/de/custom-error.json
+++ b/src/main/webapp/i18n/de/custom-error.json
@@ -2,6 +2,7 @@
     "error": {
         "shareSubscriptionPositivQuantity": "Zeichnungen von Geschäftsanteilen erfordern eine positive Stückzahl",
         "shareCancellationNegativeQuantity": "Kündigungen von Geschäftsanteilen erfordern eine negative Stückzahl",
-        "shareTransactionImmutable": "Transaktionen mit Geschäftsanteilen sind unveränderlich"
+        "shareTransactionImmutable": "Transaktionen mit Geschäftsanteilen sind unveränderlich",
+        "membershipNotDeletable": "Mitgliedschaft kann nicht gelöscht werden, setze stattdessen das 'untilDate'"
     }
 }
diff --git a/src/main/webapp/i18n/en/custom-error.json b/src/main/webapp/i18n/en/custom-error.json
index 16aed172..2eaeb0ff 100644
--- a/src/main/webapp/i18n/en/custom-error.json
+++ b/src/main/webapp/i18n/en/custom-error.json
@@ -2,6 +2,7 @@
     "error": {
         "shareSubscriptionPositivQuantity": "Share subscriptions require a positive quantity",
         "shareCancellationNegativeQuantity": "Share cancellations require a negative quantity",
-        "shareTransactionImmutable": "Share transactions are immutable"
+        "shareTransactionImmutable": "Share transactions are immutable",
+        "membershipNotDeletable": "Membership cannot be deleted, instead set 'untilDate'"
     }
 }
diff --git a/src/test/java/org/hostsharing/hsadminng/service/MembershipServiceUnitTest.java b/src/test/java/org/hostsharing/hsadminng/service/MembershipServiceUnitTest.java
new file mode 100644
index 00000000..45c5969f
--- /dev/null
+++ b/src/test/java/org/hostsharing/hsadminng/service/MembershipServiceUnitTest.java
@@ -0,0 +1,40 @@
+package org.hostsharing.hsadminng.service;
+
+import org.apache.commons.lang3.RandomUtils;
+import org.hostsharing.hsadminng.repository.MembershipRepository;
+import org.hostsharing.hsadminng.service.mapper.MembershipMapper;
+import org.hostsharing.hsadminng.web.rest.errors.BadRequestAlertException;
+import org.junit.Rule;
+import org.junit.Test;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.catchThrowableOfType;
+
+public class MembershipServiceUnitTest {
+
+    @Rule
+    public MockitoRule mockitoRule = MockitoJUnit.rule();
+
+    @Mock
+    private MembershipRepository membershipRepository;
+
+    @Mock
+    private MembershipMapper membershipMapper;
+
+    @InjectMocks
+    private MembershipService membershipService;
+
+    @Test
+    public void deleteIsRejectedForMembership() {
+        // when
+        final Throwable throwException = catchThrowableOfType(() -> membershipService.delete(RandomUtils.nextLong()), BadRequestAlertException.class);
+
+        // then
+        assertThat(throwException).isEqualToComparingFieldByField(
+            new BadRequestAlertException("Membership cannot be deleted", "membership", "membershipNotDeletable"));
+    }
+}
diff --git a/src/test/java/org/hostsharing/hsadminng/service/ShareServiceUnitTest.java b/src/test/java/org/hostsharing/hsadminng/service/ShareServiceUnitTest.java
index 826f0a17..3cdfef4e 100644
--- a/src/test/java/org/hostsharing/hsadminng/service/ShareServiceUnitTest.java
+++ b/src/test/java/org/hostsharing/hsadminng/service/ShareServiceUnitTest.java
@@ -32,7 +32,7 @@ public class ShareServiceUnitTest {
     private ShareRepository shareRepository;
 
     @Mock
-    private ShareMapper shareMapper; // = new ShareMapperImpl();
+    private ShareMapper shareMapper;
 
     @InjectMocks
     private ShareService shareService;