diff --git a/internal/schemautil/custom_diff.go b/internal/schemautil/custom_diff.go
index 5f149295b..9603f2406 100644
--- a/internal/schemautil/custom_diff.go
+++ b/internal/schemautil/custom_diff.go
@@ -6,11 +6,15 @@ import (
 	"strings"
 
 	"github.com/aiven/aiven-go-client/v2"
+	avngen "github.com/aiven/go-client-codegen"
+	"github.com/aiven/go-client-codegen/handler/service"
 	"github.com/docker/go-units"
 	"github.com/hashicorp/go-cty/cty"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/customdiff"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
 	"golang.org/x/exp/slices"
+
+	"github.com/aiven/terraform-provider-aiven/internal/common"
 )
 
 func CustomizeDiffGenericService(serviceType string) schema.CustomizeDiffFunc {
@@ -27,7 +31,10 @@ func CustomizeDiffGenericService(serviceType string) schema.CustomizeDiffFunc {
 		),
 		customdiff.IfValueChange("additional_disk_space",
 			ShouldNotBeEmpty,
-			CustomizeDiffCheckDiskSpace,
+			customdiff.Sequence(
+				CustomizeDiffCheckDiskSpace,
+				CustomizeDiffAdditionalDiskSpace,
+			),
 		),
 		customdiff.IfValueChange("service_integrations",
 			ShouldNotBeEmpty,
@@ -254,3 +261,31 @@ func checkForMultipleValues(v cty.Value) error {
 
 	return nil
 }
+
+// CustomizeDiffAdditionalDiskSpace checks that additional_disk_space is not set if autoscaler is enabled
+func CustomizeDiffAdditionalDiskSpace(ctx context.Context, diff *schema.ResourceDiff, _ interface{}) error {
+	client, err := common.GenClient()
+	if err != nil {
+		return err
+	}
+
+	s, err := client.ServiceGet(ctx, diff.Get("project").(string), diff.Get("service_name").(string))
+	if avngen.IsNotFound(err) {
+		// The service does not exist, so we cannot check if autoscaler is enabled
+		return nil
+	}
+
+	if err != nil {
+		return err
+	}
+
+	for _, i := range s.ServiceIntegrations {
+		if i.IntegrationType == service.IntegrationTypeAutoscaler {
+			// Autoscaler is enabled, so we cannot set additional_disk_space
+			return ErrAutoscalerConflict
+		}
+	}
+
+	// Autoscaler is not enabled, so additional_disk_space will be 0
+	return diff.SetNew("additional_disk_space", "0")
+}
diff --git a/internal/sdkprovider/service/pg/pg_test.go b/internal/sdkprovider/service/pg/pg_test.go
index 22eb37a56..13290a95b 100644
--- a/internal/sdkprovider/service/pg/pg_test.go
+++ b/internal/sdkprovider/service/pg/pg_test.go
@@ -265,7 +265,7 @@ func TestAccAivenPG_deleting_additional_disk_size(t *testing.T) {
 					resource.TestCheckResourceAttr(resourceName, "maintenance_window_dow", "monday"),
 					resource.TestCheckResourceAttr(resourceName, "maintenance_window_time", "10:00:00"),
 					resource.TestCheckResourceAttr(resourceName, "disk_space_default", "80GiB"),
-					resource.TestCheckResourceAttr(resourceName, "disk_space_used", "100GiB"),
+					resource.TestCheckResourceAttr(resourceName, "disk_space_used", "80GiB"),
 					resource.TestCheckResourceAttr(resourceName, "termination_protection", "false"),
 				),
 			},