diff --git a/sjson.go b/sjson.go
index 9cf3f93..ff34826 100644
--- a/sjson.go
+++ b/sjson.go
@@ -166,6 +166,10 @@ func atoui(r pathResult) (n int, ok bool) {
 	if r.force {
 		return 0, false
 	}
+	if len(r.part) == 0 {
+		// An empty key is a valid object key, not the number zero.
+		return 0, false
+	}
 	for i := 0; i < len(r.part); i++ {
 		if r.part[i] < '0' || r.part[i] > '9' {
 			return 0, false
@@ -515,9 +519,6 @@ type sliceHeader struct {
 
 func set(jstr, path, raw string,
 	stringify, del, optimistic, inplace bool) ([]byte, error) {
-	if path == "" {
-		return []byte(jstr), &errorType{"path cannot be empty"}
-	}
 	if !del && optimistic && isOptimisticPath(path) {
 		res := gjson.Get(jstr, path)
 		if res.Exists() && res.Index > 0 {
diff --git a/sjson_test.go b/sjson_test.go
index aa3d968..f0c5373 100644
--- a/sjson_test.go
+++ b/sjson_test.go
@@ -351,3 +351,47 @@ func TestIssue61(t *testing.T) {
 		t.Fail()
 	}
 }
+
+func TestEmptyKeyIssue77(t *testing.T) {
+	const json = `{"name":{"first":"Janet"},"age":47,"":"foo"}`
+
+	// An empty key is a valid object key and gjson reads it, so sjson has to
+	// be able to write and delete it too.
+	if gjson.Get(json, "").String() != "foo" {
+		t.Fatalf("gjson cannot read the empty key")
+	}
+
+	testRaw(t, setString, `{"name":{"first":"Janet"},"age":47,"":"bar"}`,
+		json, "", "bar")
+	testRaw(t, setDelete, `{"name":{"first":"Janet"},"age":47}`,
+		json, "", nil)
+
+	// setting an empty key that is not there yet adds it
+	testRaw(t, setString, `{"a":1,"":"bar"}`, `{"a":1}`, "", "bar")
+	testRaw(t, setString, `{"":"bar"}`, `{}`, "", "bar")
+
+	// deleting an empty key that is not there is a no-op, like any other
+	// missing key
+	testRaw(t, setDelete, `{"a":1}`, `{"a":1}`, "", nil)
+
+	// an empty key is a key, never the array index zero
+	testRaw(t, setInt, `{"x":1,"a":{"":2}}`, `{"x":1}`, "a.", 2)
+	testRaw(t, setInt, `{"a":{"b":{"":2}}}`, `{}`, "a.b.", 2)
+	testRaw(t, setInt, `{"a":{"":{"b":2}}}`, `{}`, "a..b", 2)
+
+	// whatever sjson writes for an empty key, gjson has to read back
+	out, err := Set(`{"x":1}`, "a.", 2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res := gjson.Get(out, "a."); !res.Exists() || res.Int() != 2 {
+		t.Fatalf("expected gjson to read back '2', got '%v' from '%v'",
+			res.Raw, out)
+	}
+
+	// an empty key still cannot address an array element, and reports the
+	// same error as any other non-numeric key
+	if _, err := Set(`[1,2,3]`, "", "x"); err == nil {
+		t.Fatalf("expected an error for an empty key on an array")
+	}
+}