diff --git a/packages/better-auth/src/plugins/organization/routes/crud-org.ts b/packages/better-auth/src/plugins/organization/routes/crud-org.ts
index 90e6adc8b2..f2395e073e 100644
--- a/packages/better-auth/src/plugins/organization/routes/crud-org.ts
+++ b/packages/better-auth/src/plugins/organization/routes/crud-org.ts
@@ -707,9 +707,10 @@ export const getFullOrganization = <O extends OrganizationOptions>(
 					message: ORGANIZATION_ERROR_CODES.ORGANIZATION_NOT_FOUND,
 				});
 			}
-			const isMember = organization?.members.find(
-				(member) => member.userId === session.user.id,
-			);
+			const isMember = await adapter.checkMembership({
+				userId: session.user.id,
+				organizationId: organization.id,
+			});
 			if (!isMember) {
 				await adapter.setActiveOrganization(session.session.token, null);
 				throw new APIError("FORBIDDEN", {
@@ -717,11 +718,6 @@ export const getFullOrganization = <O extends OrganizationOptions>(
 						ORGANIZATION_ERROR_CODES.USER_IS_NOT_A_MEMBER_OF_THE_ORGANIZATION,
 				});
 			}
-			if (!organization) {
-				throw new APIError("BAD_REQUEST", {
-					message: ORGANIZATION_ERROR_CODES.ORGANIZATION_NOT_FOUND,
-				});
-			}
 			type OrganizationReturn = O["teams"] extends { enabled: true }
 				? {
 						members: InferMember<O>[];