diff --git a/bin/typescript.d.ts b/bin/typescript.d.ts
index 7c97542d8afc5..19cf233ff6b62 100644
--- a/bin/typescript.d.ts
+++ b/bin/typescript.d.ts
@@ -1134,6 +1134,7 @@ declare module "typescript" {
         outDir?: string;
         preserveConstEnums?: boolean;
         project?: string;
+        projectRoot?: string;
         removeComments?: boolean;
         sourceMap?: boolean;
         sourceRoot?: string;
diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 4ba2da757e5d8..c94f93641fe8b 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -159,7 +159,15 @@ module ts {
             shortName: "w",
             type: "boolean",
             description: Diagnostics.Watch_input_files,
-        }
+        },
+        {
+            name: "projectRoot",
+            type: "string",
+            isFilePath: true,
+            description: Diagnostics.Specifies_the_directory_where_the_project_root_is_Paths_to_source_map_sources_will_appear_relative_to_this_directory,
+            paramType: Diagnostics.DIRECTORY,
+        },
+
     ];
     
     export function parseCommandLine(commandLine: string[]): ParsedCommandLine {
diff --git a/src/compiler/diagnosticInformationMap.generated.ts b/src/compiler/diagnosticInformationMap.generated.ts
index 6c79578e41c11..298290bca6ea1 100644
--- a/src/compiler/diagnosticInformationMap.generated.ts
+++ b/src/compiler/diagnosticInformationMap.generated.ts
@@ -436,6 +436,7 @@ module ts {
         File_0_must_have_extension_ts_or_d_ts: { code: 6054, category: DiagnosticCategory.Error, key: "File '{0}' must have extension '.ts' or '.d.ts'." },
         Suppress_noImplicitAny_errors_for_indexing_objects_lacking_index_signatures: { code: 6055, category: DiagnosticCategory.Message, key: "Suppress noImplicitAny errors for indexing objects lacking index signatures." },
         Do_not_emit_declarations_for_code_that_has_an_internal_annotation: { code: 6056, category: DiagnosticCategory.Message, key: "Do not emit declarations for code that has an '@internal' annotation." },
+        Specifies_the_directory_where_the_project_root_is_Paths_to_source_map_sources_will_appear_relative_to_this_directory: { code: 6057, category: DiagnosticCategory.Message, key: "Specifies the directory where the project root is. Paths to source map sources will appear relative to this directory." },
         Variable_0_implicitly_has_an_1_type: { code: 7005, category: DiagnosticCategory.Error, key: "Variable '{0}' implicitly has an '{1}' type." },
         Parameter_0_implicitly_has_an_1_type: { code: 7006, category: DiagnosticCategory.Error, key: "Parameter '{0}' implicitly has an '{1}' type." },
         Member_0_implicitly_has_an_1_type: { code: 7008, category: DiagnosticCategory.Error, key: "Member '{0}' implicitly has an '{1}' type." },
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 8a5d8d80427c8..c4df1118a071b 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1737,6 +1737,10 @@
         "category": "Message",
         "code": 6056
     },
+    "Specifies the directory where the project root is. Paths to source map sources will appear relative to this directory.": {
+        "category": "Message",
+        "code": 6057
+    },
 
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 6a2338268e899..7e29bb80e6d16 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -1784,9 +1784,11 @@ module ts {
 
                 function recordNewSourceFileStart(node: SourceFile) {
                     // Add the file to tsFilePaths
-                    // If sourceroot option: Use the relative path corresponding to the common directory path 
-                    // otherwise source locations relative to map file location
-                    var sourcesDirectoryPath = compilerOptions.sourceRoot ? host.getCommonSourceDirectory() : sourceMapDir;
+                    // If sourceroot option: use the relative path corresponding to the project root (if specified) or the common directory path 
+                    // Otherwise source locations relative to map file location
+                    var sourcesDirectoryPath = compilerOptions.sourceRoot
+                        ? compilerOptions.projectRoot || host.getCommonSourceDirectory()
+                        : sourceMapDir;
 
                     sourceMapData.sourceMapSources.push(getRelativePathToDirectoryOrUrl(sourcesDirectoryPath,
                         node.fileName,
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 12c5af21e1298..7cedb063bdb85 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -1474,6 +1474,7 @@ module ts {
         outDir?: string;
         preserveConstEnums?: boolean;
         project?: string;
+        projectRoot?: string;
         removeComments?: boolean;
         sourceMap?: boolean;
         sourceRoot?: string;