Nested master page
<%@ page language="C#" MasterPageFile="~/Default.master" %> <asp:content id="Content1" contentplaceholderid="Content1" runat=server> <asp:label runat="server" id="Label1" text="Child label1" font-bold="true"/> <br> </asp:content> <asp:content id="Content2" contentplaceholderid="Content2" runat=server> <asp:label runat="server" id="Label2" text="Child label2" font-bold="true"/> </asp:content> File: Default.master <%@ master language="C#" MasterPageFile="~/MasterDefault.master" %> <asp:content id="Content1" contentplaceholderid="MainContent" runat="server"> <asp:panel runat="server" id="panelMain" backcolor="lightyellow"> <h2>Child master</h2> <asp:panel runat="server" id="panel1" backcolor="lightblue"> <p>This is childmaster content.</p> <asp:contentplaceholder id="Content1" runat="server" /> </asp:panel> <asp:panel runat="server" id="panel2" backcolor="pink"> <p>This is childmaster content.</p> <asp:contentplaceholder id="Content2" runat="server" /> </asp:panel> </asp:panel> </asp:content> File: MasterDefault.master <%@ Master Language="C#" %> <HTML> <BODY> <form id="Form1" runat=server> <h1>Parent Master</h1> <p> <font color=red>This is Parent-master content.</font> </P> <asp:contentplaceholder id="MainContent" runat=server/> </form> </HTML> </BODY>