Declined with the following reason - chart series are preserved in the ViewState by default. You can do one of the following: 1) Either disable the ViewState of the chart or its container: ASPX: <asp:Panel ID="Panel1" runat="server" EnableViewState="false" /> C#: RadHtmlChart chart1 = new RadHtmlChart(); chart1.EnableViewState = false; 2) Or clear the chart Series collection after adding the chart to the page: RadHtmlChart chart1 = new RadHtmlChart(); chart1.ID = "myChart"; //Add the chart to the page Panel1.Controls.Add(chart1); //Clear the series after adding the chart to the page chart1.PlotArea.Series.Clear();