diff --git a/client/cost_credentials_project_assignment.go b/client/cost_credentials_project_assignment.go
index f9f5d5b7..0779f007 100644
--- a/client/cost_credentials_project_assignment.go
+++ b/client/cost_credentials_project_assignment.go
@@ -9,7 +9,9 @@ type CostCredentialProjectAssignment struct {
 func (client *ApiClient) AssignCostCredentialsToProject(projectId string, credentialId string) (CostCredentialProjectAssignment, error) {
 	var result CostCredentialProjectAssignment
 
-	err := client.http.Put("/costs/project/"+projectId+"/credentials", credentialId, &result)
+	err := client.http.Put("/costs/project/"+projectId+"/credentials", map[string]string{
+		"credentialsId": credentialId,
+	}, &result)
 	if err != nil {
 		return result, err
 	}
@@ -22,7 +24,7 @@ func (client *ApiClient) RemoveCostCredentialsFromProject(projectId string, cred
 
 func (client *ApiClient) CostCredentialIdsInProject(projectId string) ([]CostCredentialProjectAssignment, error) {
 	var result []CostCredentialProjectAssignment
-	err := client.http.Get("/costs/project/"+projectId, nil, &result)
+	err := client.http.Get("/costs/project/"+projectId+"/credentials", nil, &result)
 
 	if err != nil {
 		return nil, err
diff --git a/client/cost_credentials_project_assignment_test.go b/client/cost_credentials_project_assignment_test.go
index f6e6620c..86ea289f 100644
--- a/client/cost_credentials_project_assignment_test.go
+++ b/client/cost_credentials_project_assignment_test.go
@@ -24,7 +24,7 @@ var _ = Describe(" Cost Credentials Project Assignment", func() {
 			BeforeEach(func() {
 
 				httpCall = mockHttpClient.EXPECT().
-					Put("/costs/project/"+projectId+"/credentials", credentialId, gomock.Any()).
+					Put("/costs/project/"+projectId+"/credentials", map[string]string{"credentialsId": credentialId}, gomock.Any()).
 					Do(func(path string, request interface{}, response *CostCredentialProjectAssignment) {
 						*response = expectedResponse
 					}).Times(1)
@@ -41,7 +41,7 @@ var _ = Describe(" Cost Credentials Project Assignment", func() {
 			var actualError error
 			BeforeEach(func() {
 				httpCall = mockHttpClient.EXPECT().
-					Put("/costs/project/"+projectId+"/credentials", credentialId, gomock.Any()).
+					Put("/costs/project/"+projectId+"/credentials", map[string]string{"credentialsId": credentialId}, gomock.Any()).
 					Return(errors.New(errorInfo)).
 					Times(1)
 				_, actualError = apiClient.AssignCostCredentialsToProject(projectId, credentialId)
@@ -93,7 +93,7 @@ var _ = Describe(" Cost Credentials Project Assignment", func() {
 			expectedResponse := []CostCredentialProjectAssignment{firstResulteResponse, secondResulteResponse}
 			BeforeEach(func() {
 				httpCall = mockHttpClient.EXPECT().
-					Get("/costs/project/"+projectId, nil, gomock.Any()).
+					Get("/costs/project/"+projectId+"/credentials", nil, gomock.Any()).
 					Do(func(path string, request interface{}, response *[]CostCredentialProjectAssignment) {
 						*response = expectedResponse
 					}).Times(1)
@@ -110,7 +110,7 @@ var _ = Describe(" Cost Credentials Project Assignment", func() {
 			var actualError error
 			BeforeEach(func() {
 				httpCall = mockHttpClient.EXPECT().
-					Get("/costs/project/"+projectId, nil, gomock.Any()).
+					Get("/costs/project/"+projectId+"/credentials", nil, gomock.Any()).
 					Return(errors.New(errorInfo)).
 					Times(1)
 				_, actualError = apiClient.CostCredentialIdsInProject(projectId)
diff --git a/tests/integration/023_cost_credentials_project_assignment/conf.tf b/tests/integration/023_cost_credentials_project_assignment/conf.tf
new file mode 100644
index 00000000..8d6d2954
--- /dev/null
+++ b/tests/integration/023_cost_credentials_project_assignment/conf.tf
@@ -0,0 +1,15 @@
+terraform {
+  backend "local" {
+  }
+  required_providers {
+    env0 = {
+      source = "terraform-registry.env0.com/env0/env0"
+    }
+  }
+}
+
+provider "env0" {}
+
+variable "second_run" {
+  default = false
+}
diff --git a/tests/integration/023_cost_credentials_project_assignment/expected_outputs.json b/tests/integration/023_cost_credentials_project_assignment/expected_outputs.json
new file mode 100644
index 00000000..0967ef42
--- /dev/null
+++ b/tests/integration/023_cost_credentials_project_assignment/expected_outputs.json
@@ -0,0 +1 @@
+{}
diff --git a/tests/integration/023_cost_credentials_project_assignment/main.tf b/tests/integration/023_cost_credentials_project_assignment/main.tf
new file mode 100644
index 00000000..55bcd63e
--- /dev/null
+++ b/tests/integration/023_cost_credentials_project_assignment/main.tf
@@ -0,0 +1,23 @@
+provider "random" {}
+
+resource "random_string" "random" {
+  length    = 8
+  special   = false
+  min_lower = 8
+}
+
+resource "env0_project" "project" {
+  name        = "Test-Project-${random_string.random.result}"
+  description = "description"
+}
+
+resource "env0_aws_cost_credentials" "cost" {
+  name        = "cost-${random_string.random.result}"
+  arn         = "arn"
+  external_id = "externalid"
+}
+
+resource "env0_cost_credentials_project_assignment" "cost_project_assignment" {
+  credential_id = env0_aws_cost_credentials.cost.id
+  project_id    = env0_project.project.id
+}