diff --git a/src/Mono.WebServer.Apache/main.cs b/src/Mono.WebServer.Apache/main.cs
index f7ebfeec..e33b0524 100644
--- a/src/Mono.WebServer.Apache/main.cs
+++ b/src/Mono.WebServer.Apache/main.cs
@@ -366,7 +366,7 @@ public int RealMain (string [] args, bool root, IApplicationHost ext_apphost, bo
 				return (res) ? 0 : 1;
 			}
 
-			ApplicationServer server = new ApplicationServer (webSource);
+			ApplicationServer server = new ApplicationServer (webSource, rootDir);
 			server.Verbose = verbose;
 			server.SingleApplication = !root;
 
diff --git a/src/Mono.WebServer.FastCgi/main.cs b/src/Mono.WebServer.FastCgi/main.cs
index 1bd3c538..3dd683c3 100644
--- a/src/Mono.WebServer.FastCgi/main.cs
+++ b/src/Mono.WebServer.FastCgi/main.cs
@@ -288,7 +288,7 @@ public static int Main (string [] args)
 			root_dir = Environment.CurrentDirectory;
 			bool auto_map = false; //(bool) configmanager ["automappaths"];
                         WebSource webSource = new WebSource ();
-			appserver = new ApplicationServer (webSource);
+			appserver = new ApplicationServer (webSource, root_dir);
 			appserver.Verbose = (bool) configmanager ["verbose"];
 			
 			string applications = (string)
diff --git a/src/Mono.WebServer.XSP/main.cs b/src/Mono.WebServer.XSP/main.cs
index 718c24ae..54796814 100644
--- a/src/Mono.WebServer.XSP/main.cs
+++ b/src/Mono.WebServer.XSP/main.cs
@@ -426,7 +426,7 @@ public int RealMain (string [] args, bool root, IApplicationHost ext_apphost, bo
 				webSource = new XSPWebSource (ipaddr, port, !root);
 			}
 
-			ApplicationServer server = new ApplicationServer (webSource);
+			ApplicationServer server = new ApplicationServer (webSource, settings.RootDir);
 			server.Verbose = settings.Verbose;
 			server.SingleApplication = !root;
 
diff --git a/src/Mono.WebServer/ApplicationServer.cs b/src/Mono.WebServer/ApplicationServer.cs
index 18c4714b..e689c173 100644
--- a/src/Mono.WebServer/ApplicationServer.cs
+++ b/src/Mono.WebServer/ApplicationServer.cs
@@ -90,6 +90,7 @@ public class ApplicationServer : MarshalByRefObject
 		Socket listen_socket;
 		bool single_app;
 		Exception initialException;
+		string physicalRoot;
 		
 		Thread runner;
 
@@ -127,10 +128,20 @@ public class ApplicationServer : MarshalByRefObject
 				return iep.Port;
 			}
 		}
+
+		public string PhysicalRoot {
+			get { return physicalRoot; }
+		}
 		
-		public ApplicationServer (WebSource source)
+		public ApplicationServer (WebSource source, string physicalRoot)
 		{
-			webSource = source;
+			if (source == null)
+				throw new ArgumentNullException ("source");
+			if (physicalRoot == null || physicalRoot.Length == 0)
+				throw new ArgumentNullException ("physicalRoot");
+			
+			this.webSource = source;
+			this.physicalRoot = physicalRoot;
 		} 
 
 		public bool Verbose {
diff --git a/src/Mono.WebServer/MonoWorkerRequest.cs b/src/Mono.WebServer/MonoWorkerRequest.cs
index b52c62c9..8dc8a81d 100644
--- a/src/Mono.WebServer/MonoWorkerRequest.cs
+++ b/src/Mono.WebServer/MonoWorkerRequest.cs
@@ -175,8 +175,12 @@ public MapPathEventArgs (string path)
 	/// </summary>
 	public abstract class MonoWorkerRequest : SimpleWorkerRequest
 	{
+		static readonly char[] mapPathTrimStartChars = { '/' };
+
 		static bool runningOnWindows;
 		static bool checkFileAccess = true;
+		static bool needToReplacePathSeparator;
+		static char pathSeparatorChar;
 		
 		/// <summary>
 		///    Contains the application host used by the current
@@ -218,6 +222,8 @@ public abstract class MonoWorkerRequest : SimpleWorkerRequest
 		///    as read from the application host.
 		/// </summary>
 		string hostPath;
+
+		string hostPhysicalRoot;
 		
 		/// <summary>
 		///    Contains the <see cref="EndOfSendNotification" />
@@ -274,6 +280,11 @@ static MonoWorkerRequest ()
 #endif
                         );
 
+			if (Path.DirectorySeparatorChar != '/') {
+				needToReplacePathSeparator = true;
+				pathSeparatorChar = Path.DirectorySeparatorChar;
+			}
+
 			try {
 #if NET_2_0
 				string v = ConfigurationManager.AppSettings ["MonoServerCheckHiddenFiles"];
@@ -381,6 +392,15 @@ public MonoWorkerRequest (IApplicationHost appHost)
 			}
 		}
 
+		string HostPhysicalRoot {
+			get {
+				if (hostPhysicalRoot == null)
+					hostPhysicalRoot = appHostBase.Server.PhysicalRoot;
+
+				return hostPhysicalRoot;
+			}
+		}
+
 		/// <summary>
 		///    Gets the content encoding used by the current instance.
 		/// </summary>
@@ -595,30 +615,67 @@ string DoMapPathEvent (string path)
 		///    register a <see cref="MapPathEventHandler" /> with <see
 		///    cref="MapPathEvent" />.
 		/// </remarks>
+		//
+		// The logic here is as follows:
+		//
+		// If path is equal to the host's virtual path (including trailing slash),
+		// return the host virtual path.
+		//
+		// If path is absolute (starts with '/') then check if it's under our host vpath. If
+		// it is, base the mapping under the virtual application's physical path. If it
+		// isn't use the physical root of the application server to return the mapped
+		// path. If you have just one application configured, then the values computed in
+		// both of the above cases will be the same. If you have several applications
+		// configured for this xsp/mod-mono-server instance, then virtual paths outside our
+		// application virtual path will return physical paths relative to the server's
+		// physical root, not application's. This is consistent with the way IIS worker
+		// request works. See bug #575600
+		//
 		public override string MapPath (string path)
 		{
 			string eventResult = DoMapPathEvent (path);
 			if (eventResult != null)
 				return eventResult;
 
-			if (path == null || path.Length == 0 || path == HostVPath)
-				return HostPath.Replace ('/', Path.DirectorySeparatorChar);
+			string hostVPath = HostVPath;
+			int hostVPathLen = HostVPath.Length;
+			int pathLen = path != null ? path.Length : 0;
+			bool inThisApp;
+#if NET_2_0
+			inThisApp = path.StartsWith (hostVPath, StringComparison.Ordinal);
+#else
+			inThisApp = path.StartsWith (hostVPath);
+#endif
+			if (pathLen == 0 || (inThisApp && (pathLen == hostVPathLen || (pathLen == hostVPathLen + 1 && path [pathLen - 1] == '/')))) {
+				if (needToReplacePathSeparator)
+					return HostPath.Replace ('/', pathSeparatorChar);
+				return HostPath;
+			}
 
-			if (path [0] == '~' && path.Length > 2 && path [1] == '/')
-				path = path.Substring (1);
+			string basePath = null;
+			switch (path [0]) {
+				case '~':
+					if (path.Length >= 2 && path [1] == '/')
+						path = path.Substring (1);
+					break;
+
+				case '/':
+					if (!inThisApp)
+						basePath = HostPhysicalRoot;
+					break;
+			}
 
-			int len = HostVPath.Length;
-			if (path.StartsWith (HostVPath) && (path.Length == len || path [len] == '/'))
-				path = path.Substring (len + 1);
+			if (basePath == null)
+				basePath = HostPath;
 
-			while (path.Length > 0 && path [0] == '/') {
-				path = path.Substring (1);
-			}
+			if (inThisApp && (path.Length == hostVPathLen || path [hostVPathLen] == '/'))
+				path = path.Substring (hostVPathLen + 1);
 
-			if (Path.DirectorySeparatorChar != '/')
-				path = path.Replace ('/', Path.DirectorySeparatorChar);
+			path = path.TrimStart (mapPathTrimStartChars);
+			if (needToReplacePathSeparator)
+				path = path.Replace ('/', pathSeparatorChar);
 
-			return Path.Combine (HostPath, path);
+			return Path.Combine (basePath, path);
 		}
 
 		/// <summary>