[asp.net-mvc-2] How to Set RadioButtonFor() in ASp.net MVC 2 as Checked by default

You need to add 'checked' htmlAttribute in RadioButtonFor, if the radiobutton's value matches with Model.Gender value.

@{
        foreach (var item in Model.GenderList)
        {
            <div class="btn-group" role="group">
               <label class="btn btn-default">
                   @Html.RadioButtonFor(m => m.Gender, item.Key, (int)Model.Gender==item.Key ? new { @checked = "checked" } : null)
                   @item.Value
              </label>
            </div>
        }
    }

For complete code see below link: To render bootstrap radio button group with default checked. stackoverflow answer link