To reproduce: public Form1() { InitializeComponent(); this.radMaskedEditBox1.Mask = "9999999999"; this.radMaskedEditBox1.MaskType = Telerik.WinControls.UI.MaskType.Standard; this.radMaskedEditBox1.PromptChar = Convert.ToChar(" "); } private void radButton1_Click(object sender, EventArgs e) { this.radMaskedEditBox1.Clear(); this.radLabel1.Text = "Value = " + this.radMaskedEditBox1.Value + Environment.NewLine + "Text = " + this.radMaskedEditBox1.Text; } Workaround: set the Value to null as well.