diff --git a/src/main/java/io/craftgate/adapter/PaymentAdapter.java b/src/main/java/io/craftgate/adapter/PaymentAdapter.java
index 0cc2260c..932ef8c9 100644
--- a/src/main/java/io/craftgate/adapter/PaymentAdapter.java
+++ b/src/main/java/io/craftgate/adapter/PaymentAdapter.java
@@ -142,6 +142,12 @@ public PaymentTransactionRefundResponse retrievePaymentTransactionRefund(Long id
         return HttpClient.get(requestOptions.getBaseUrl() + path, createHeaders(path, requestOptions), PaymentTransactionRefundResponse.class);
     }
 
+    public PaymentTransactionRefundResponse refundPaymentTransactionMarkAsRefunded(RefundPaymentTransactionMarkAsRefundedRequest refundPaymentTransactionMarkAsRefundedRequest) {
+        String path = "/payment/v1/refund-transactions/manual";
+        return HttpClient.post(requestOptions.getBaseUrl() + path, createHeaders(refundPaymentTransactionMarkAsRefundedRequest, path, requestOptions),
+                refundPaymentTransactionMarkAsRefundedRequest, PaymentTransactionRefundResponse.class);
+    }
+
     public PaymentRefundResponse refundPayment(RefundPaymentRequest refundPaymentRequest) {
         String path = "/payment/v1/refunds";
         return HttpClient.post(requestOptions.getBaseUrl() + path, createHeaders(refundPaymentRequest, path, requestOptions),
diff --git a/src/main/java/io/craftgate/request/RefundPaymentTransactionMarkAsRefundedRequest.java b/src/main/java/io/craftgate/request/RefundPaymentTransactionMarkAsRefundedRequest.java
new file mode 100644
index 00000000..4ee8d30b
--- /dev/null
+++ b/src/main/java/io/craftgate/request/RefundPaymentTransactionMarkAsRefundedRequest.java
@@ -0,0 +1,20 @@
+package io.craftgate.request;
+
+import io.craftgate.model.RefundDestinationType;
+import lombok.Builder;
+import lombok.Data;
+
+@Data
+@Builder
+public class RefundPaymentTransactionMarkAsRefundedRequest {
+
+    private Long paymentTransactionRefundId;
+    private String conversationId;
+    private String description;
+
+    @Builder.Default
+    private RefundDestinationType refundDestinationType = RefundDestinationType.PROVIDER;
+
+    @Builder.Default
+    private Boolean chargeFromMe = false;
+}
diff --git a/src/test/java/io/craftgate/sample/PaymentSample.java b/src/test/java/io/craftgate/sample/PaymentSample.java
index e63561ed..f1681fea 100644
--- a/src/test/java/io/craftgate/sample/PaymentSample.java
+++ b/src/test/java/io/craftgate/sample/PaymentSample.java
@@ -915,7 +915,7 @@ void init_garanti_pay_payment() {
                 .paymentGroup(PaymentGroup.LISTING_OR_SUBSCRIPTION)
                 .items(items)
                 .installments(installments)
-                .enabledInstallments(Arrays.asList(2,3))
+                .enabledInstallments(Arrays.asList(2, 3))
                 .build();
 
         InitGarantiPayPaymentResponse response = craftgate.payment().initGarantiPayPayment(request);
@@ -1579,6 +1579,18 @@ void retrieve_payment_transaction_refund() {
         assertEquals(RefundStatus.SUCCESS, response.getStatus());
     }
 
+    @Test
+    void refund_payment_transaction_mark_as_refunded() {
+        RefundPaymentTransactionMarkAsRefundedRequest request = RefundPaymentTransactionMarkAsRefundedRequest.builder()
+                .paymentTransactionRefundId(1L)
+                .description("marked as refunded")
+                .build();
+
+        PaymentTransactionRefundResponse response = craftgate.payment().refundPaymentTransactionMarkAsRefunded(request);
+        assertNotNull(response);
+        assertEquals(RefundStatus.SUCCESS, response.getStatus());
+    }
+
     @Test
     void store_card() {
         final StoreCardRequest storeCardRequest = StoreCardRequest.builder()