diff --git a/bigquery/integration_test.go b/bigquery/integration_test.go
index 94d98f1401d..093188187e0 100644
--- a/bigquery/integration_test.go
+++ b/bigquery/integration_test.go
@@ -2916,18 +2916,33 @@ func TestIntegration_RoutineJSUDF(t *testing.T) {
 	// Create a scalar UDF routine via API.
 	routineID := routineIDs.New()
 	routine := dataset.Routine(routineID)
-	err := routine.Create(ctx, &RoutineMetadata{
+	meta := &RoutineMetadata{
 		Language: "JAVASCRIPT", Type: "SCALAR_FUNCTION",
-		Description: "capitalizes using javascript",
+		Description:      "capitalizes using javascript",
+		DeterminismLevel: Deterministic,
 		Arguments: []*RoutineArgument{
 			{Name: "instr", Kind: "FIXED_TYPE", DataType: &StandardSQLDataType{TypeKind: "STRING"}},
 		},
 		ReturnType: &StandardSQLDataType{TypeKind: "STRING"},
 		Body:       "return instr.toUpperCase();",
-	})
-	if err != nil {
+	}
+	if err := routine.Create(ctx, meta); err != nil {
 		t.Fatalf("Create: %v", err)
 	}
+
+	newMeta := &RoutineMetadataToUpdate{
+		Language:    meta.Language,
+		Body:        meta.Body,
+		Arguments:   meta.Arguments,
+		Description: meta.Description,
+		ReturnType:  meta.ReturnType,
+		Type:        meta.Type,
+
+		DeterminismLevel: NotDeterministic,
+	}
+	if _, err := routine.Update(ctx, newMeta, ""); err != nil {
+		t.Fatalf("Update: %v", err)
+	}
 }
 
 func TestIntegration_RoutineComplexTypes(t *testing.T) {
diff --git a/bigquery/routine.go b/bigquery/routine.go
index 58f1a78b798..6f6c3a177f4 100644
--- a/bigquery/routine.go
+++ b/bigquery/routine.go
@@ -129,13 +129,27 @@ func (r *Routine) Delete(ctx context.Context) (err error) {
 	return req.Do()
 }
 
+// RoutineDeterminism specifies the level of determinism that javascript User Defined Functions
+// exhibit.
+type RoutineDeterminism string
+
+const (
+	// Deterministic indicates that two calls with the same input to a UDF yield the same output.
+	Deterministic RoutineDeterminism = "DETERMINISTIC"
+	// NotDeterministic indicates that the output of the UDF is not guaranteed to yield the same
+	// output each time for a given set of inputs.
+	NotDeterministic RoutineDeterminism = "NOT_DETERMINISTIC"
+)
+
 // RoutineMetadata represents details of a given BigQuery Routine.
 type RoutineMetadata struct {
 	ETag string
 	// Type indicates the type of routine, such as SCALAR_FUNCTION or PROCEDURE.
-	Type             string
-	CreationTime     time.Time
-	Description      string
+	Type         string
+	CreationTime time.Time
+	Description  string
+	// DeterminismLevel is only applicable to Javascript UDFs.
+	DeterminismLevel RoutineDeterminism
 	LastModifiedTime time.Time
 	// Language of the routine, such as SQL or JAVASCRIPT.
 	Language string
@@ -161,6 +175,7 @@ func (rm *RoutineMetadata) toBQ() (*bq.Routine, error) {
 		return r, nil
 	}
 	r.Description = rm.Description
+	r.DeterminismLevel = string(rm.DeterminismLevel)
 	r.Language = rm.Language
 	r.RoutineType = rm.Type
 	r.DefinitionBody = rm.Body
@@ -280,6 +295,7 @@ func routineArgumentsToBQ(in []*RoutineArgument) ([]*bq.Argument, error) {
 type RoutineMetadataToUpdate struct {
 	Arguments         []*RoutineArgument
 	Description       optional.String
+	DeterminismLevel  optional.String
 	Type              optional.String
 	Language          optional.String
 	Body              optional.String
@@ -299,6 +315,21 @@ func (rm *RoutineMetadataToUpdate) toBQ() (*bq.Routine, error) {
 		r.Description = optional.ToString(rm.Description)
 		forceSend("Description")
 	}
+	if rm.DeterminismLevel != nil {
+		processed := false
+		// Allow either string or RoutineDeterminism, a type based on string.
+		if x, ok := rm.DeterminismLevel.(RoutineDeterminism); ok {
+			r.DeterminismLevel = string(x)
+			processed = true
+		}
+		if x, ok := rm.DeterminismLevel.(string); ok {
+			r.DeterminismLevel = x
+			processed = true
+		}
+		if !processed {
+			panic(fmt.Sprintf("DeterminismLevel should be either type string or RoutineDetermism in update, got %T", rm.DeterminismLevel))
+		}
+	}
 	if rm.Arguments != nil {
 		if len(rm.Arguments) == 0 {
 			nullField("Arguments")
@@ -348,6 +379,7 @@ func bqToRoutineMetadata(r *bq.Routine) (*RoutineMetadata, error) {
 		Type:              r.RoutineType,
 		CreationTime:      unixMillisToTime(r.CreationTime),
 		Description:       r.Description,
+		DeterminismLevel:  RoutineDeterminism(r.DeterminismLevel),
 		LastModifiedTime:  unixMillisToTime(r.LastModifiedTime),
 		Language:          r.Language,
 		ImportedLibraries: r.ImportedLibraries,
diff --git a/bigquery/routine_test.go b/bigquery/routine_test.go
index 00122a44e0c..f0c122ea113 100644
--- a/bigquery/routine_test.go
+++ b/bigquery/routine_test.go
@@ -80,6 +80,7 @@ func TestRoutineTypeConversions(t *testing.T) {
 				DefinitionBody:   "body",
 				Description:      "desc",
 				Etag:             "etag",
+				DeterminismLevel: "DETERMINISTIC",
 				RoutineType:      "type",
 				Language:         "lang",
 				ReturnType:       &bq.StandardSqlDataType{TypeKind: "INT64"},
@@ -88,6 +89,7 @@ func TestRoutineTypeConversions(t *testing.T) {
 				CreationTime:     aTime,
 				LastModifiedTime: aTime,
 				Description:      "desc",
+				DeterminismLevel: Deterministic,
 				Body:             "body",
 				ETag:             "etag",
 				Type:             "type",