diff --git a/optional_unmarshaljson.go b/optional_unmarshaljson.go
index 001dc45..4e87d46 100644
--- a/optional_unmarshaljson.go
+++ b/optional_unmarshaljson.go
@@ -18,7 +18,7 @@ func (receiver *Optional[T]) UnmarshalJSON(data []byte) error {
 	}
 
 	switch interface{}(&receiver.value).(type) {
-	case *bool, *string, json.Unmarshaler:
+	case *bool, *int64, *uint64, *string, *json.Number, json.Unmarshaler:
 		// these are OK.
 	default:
 		return erorr.Errorf("opt: cannot unmarshal into something of type %T from JSON because pointer to parameterized type is ‘%T’ rather than ‘*bool’, ‘*string’, or ‘json.Unmarshaler’", receiver, &receiver.value)
diff --git a/optional_unmarshaljson_int64_test.go b/optional_unmarshaljson_int64_test.go
new file mode 100644
index 0000000..31951a3
--- /dev/null
+++ b/optional_unmarshaljson_int64_test.go
@@ -0,0 +1,82 @@
+package opt_test
+
+import (
+	"testing"
+
+	"encoding/json"
+
+	"sourcecode.social/reiver/go-opt"
+)
+
+func TestOptional_UnmarshalJSON_int64(t *testing.T) {
+
+	tests := []struct{
+		JSON string
+		Expected opt.Optional[int64]
+	}{
+		{
+			JSON: `-255`,
+			Expected: opt.Something(int64(-255)),
+		},
+
+
+		{
+			JSON: `-1`,
+			Expected: opt.Something(int64(-1)),
+		},
+		{
+			JSON: `0`,
+			Expected: opt.Something(int64(0)),
+		},
+		{
+			JSON: `1`,
+			Expected: opt.Something(int64(1)),
+		},
+
+
+		{
+			JSON: `255`,
+			Expected: opt.Something(int64(255)),
+		},
+	}
+
+	for testNumber, test := range tests {
+
+		var actual opt.Optional[int64]
+
+		err := json.Unmarshal([]byte(test.JSON), &actual)
+		if nil != err {
+			t.Errorf("For test #%d, did not expect an error but actually got one.", testNumber)
+			t.Logf("ERROR: (%T) %s", err, err)
+			t.Logf("JSON: %q", test.JSON)
+			t.Logf("EXPECTED: %#v", test.Expected)
+			t.Logf("ACTUAL:   %#v", actual)
+			continue
+		}
+
+		{
+			expected := test.Expected
+
+			if expected != actual {
+				t.Errorf("For test #%d, the actual value of the optional type is not what was expected.", testNumber)
+				t.Logf("EXPECTED: %#v", expected)
+				t.Logf("ACTUAL:   %#v", actual)
+				t.Logf("JSON: %q", test.JSON)
+				continue
+			}
+		}
+	}
+}
+
+func TestOptional_UnmarshalJSON_int64_fail(t *testing.T) {
+
+	var op opt.Optional[int64]
+
+	var jason string = `false`
+
+	err := json.Unmarshal([]byte(jason), &op)
+	if nil == err {
+		t.Errorf("Expected an error but did not actually get one.")
+		return
+	}
+}
diff --git a/optional_unmarshaljson_uint64_test.go b/optional_unmarshaljson_uint64_test.go
new file mode 100644
index 0000000..42178bd
--- /dev/null
+++ b/optional_unmarshaljson_uint64_test.go
@@ -0,0 +1,72 @@
+package opt_test
+
+import (
+	"testing"
+
+	"encoding/json"
+
+	"sourcecode.social/reiver/go-opt"
+)
+
+func TestOptional_UnmarshalJSON_uint64(t *testing.T) {
+
+	tests := []struct{
+		JSON string
+		Expected opt.Optional[uint64]
+	}{
+		{
+			JSON: `0`,
+			Expected: opt.Something(uint64(0)),
+		},
+		{
+			JSON: `1`,
+			Expected: opt.Something(uint64(1)),
+		},
+
+
+		{
+			JSON: `255`,
+			Expected: opt.Something(uint64(255)),
+		},
+	}
+
+	for testNumber, test := range tests {
+
+		var actual opt.Optional[uint64]
+
+		err := json.Unmarshal([]byte(test.JSON), &actual)
+		if nil != err {
+			t.Errorf("For test #%d, did not expect an error but actually got one.", testNumber)
+			t.Logf("ERROR: (%T) %s", err, err)
+			t.Logf("JSON: %q", test.JSON)
+			t.Logf("EXPECTED: %#v", test.Expected)
+			t.Logf("ACTUAL:   %#v", actual)
+			continue
+		}
+
+		{
+			expected := test.Expected
+
+			if expected != actual {
+				t.Errorf("For test #%d, the actual value of the optional type is not what was expected.", testNumber)
+				t.Logf("EXPECTED: %#v", expected)
+				t.Logf("ACTUAL:   %#v", actual)
+				t.Logf("JSON: %q", test.JSON)
+				continue
+			}
+		}
+	}
+}
+
+func TestOptional_UnmarshalJSON_uint64_fail(t *testing.T) {
+
+	var op opt.Optional[uint64]
+
+	var jason string = `false`
+
+	err := json.Unmarshal([]byte(jason), &op)
+	if nil == err {
+		t.Errorf("Expected an error but did not actually get one.")
+		return
+	}
+}