diff --git a/extensions/css/server/src/cssServerMain.ts b/extensions/css/server/src/cssServerMain.ts
index 18f9eea6d89..fd325c05f18 100644
--- a/extensions/css/server/src/cssServerMain.ts
+++ b/extensions/css/server/src/cssServerMain.ts
@@ -10,7 +10,7 @@ import {
 } from 'vscode-languageserver';
 
 import {getCSSLanguageService, getSCSSLanguageService, getLESSLanguageService, LanguageSettings, LanguageService} from './cssLanguageService';
-import {Stylesheet} from './parser/cssNodes';
+import {getStylesheetCache} from './stylesheetCache';
 
 import * as nls from 'vscode-nls';
 nls.config(process.env['VSCODE_NLS_CONFIG']);
@@ -29,6 +29,9 @@ export interface Settings {
 // stdin / stdout for message passing
 let connection: IConnection = createConnection(new IPCMessageReader(process), new IPCMessageWriter(process));
 
+console.log = connection.console.log.bind(connection.console);
+console.error = connection.console.error.bind(connection.console);
+
 // Create a simple text document manager. The text document manager
 // supports full document sync only
 let documents: TextDocuments = new TextDocuments();
@@ -36,6 +39,13 @@ let documents: TextDocuments = new TextDocuments();
 // for open, change and close text document events
 documents.listen(connection);
 
+let stylesheets = getStylesheetCache(10, 60, document => getLanguageService(document).parseStylesheet(document));
+documents.onDidClose(e => {
+	stylesheets.onDocumentRemoved(e.document);
+});
+connection.onShutdown(() => {
+	stylesheets.dispose();
+});
 
 // After the server has started the client sends an initilize request. The server receives
 // in the passed params the rootPath of the workspace plus the client capabilites.
@@ -87,62 +97,58 @@ function updateConfiguration(settings: Settings) {
 }
 
 function validateTextDocument(textDocument: TextDocument): void {
-	let stylesheet = getStylesheet(textDocument);
+	let stylesheet = stylesheets.getStylesheet(textDocument);
 	getLanguageService(textDocument).doValidation(textDocument, stylesheet).then(diagnostics => {
 		// Send the computed diagnostics to VSCode.
 		connection.sendDiagnostics({ uri: textDocument.uri, diagnostics });
 	});
 }
 
-function getStylesheet(document: TextDocument): Stylesheet {
-	return getLanguageService(document).parseStylesheet(document);
-}
-
 connection.onCompletion(textDocumentPosition => {
 	let document = documents.get(textDocumentPosition.textDocument.uri);
-	let stylesheet = getStylesheet(document);
+	let stylesheet = stylesheets.getStylesheet(document);
 	return getLanguageService(document).doComplete(document, textDocumentPosition.position, stylesheet);
 });
 
 connection.onHover(textDocumentPosition => {
 	let document = documents.get(textDocumentPosition.textDocument.uri);
-	let styleSheet = getStylesheet(document);
+	let styleSheet = stylesheets.getStylesheet(document);
 	return getLanguageService(document).doHover(document, textDocumentPosition.position, styleSheet);
 });
 
 connection.onDocumentSymbol(documentSymbolParams => {
 	let document = documents.get(documentSymbolParams.textDocument.uri);
-	let stylesheet = getStylesheet(document);
+	let stylesheet = stylesheets.getStylesheet(document);
 	return getLanguageService(document).findDocumentSymbols(document, stylesheet);
 });
 
 connection.onDefinition(documentSymbolParams => {
 	let document = documents.get(documentSymbolParams.textDocument.uri);
-	let stylesheet = getStylesheet(document);
+	let stylesheet = stylesheets.getStylesheet(document);
 	return getLanguageService(document).findDefinition(document, documentSymbolParams.position, stylesheet);
 });
 
 connection.onDocumentHighlight(documentSymbolParams => {
 	let document = documents.get(documentSymbolParams.textDocument.uri);
-	let stylesheet = getStylesheet(document);
+	let stylesheet = stylesheets.getStylesheet(document);
 	return getLanguageService(document).findDocumentHighlights(document, documentSymbolParams.position, stylesheet);
 });
 
 connection.onReferences(referenceParams => {
 	let document = documents.get(referenceParams.textDocument.uri);
-	let stylesheet = getStylesheet(document);
+	let stylesheet = stylesheets.getStylesheet(document);
 	return getLanguageService(document).findReferences(document, referenceParams.position, stylesheet);
 });
 
 connection.onCodeAction(codeActionParams => {
 	let document = documents.get(codeActionParams.textDocument.uri);
-	let stylesheet = getStylesheet(document);
+	let stylesheet = stylesheets.getStylesheet(document);
 	return getLanguageService(document).doCodeActions(document, codeActionParams.range, codeActionParams.context, stylesheet);
 });
 
 connection.onRequest(ColorSymbolRequest.type, uri => {
 	let document = documents.get(uri);
-	let stylesheet = getStylesheet(document);
+	let stylesheet = stylesheets.getStylesheet(document);
 	return getLanguageService(document).findColorSymbols(document, stylesheet);
 });
 
diff --git a/extensions/css/server/src/stylesheetCache.ts b/extensions/css/server/src/stylesheetCache.ts
new file mode 100644
index 00000000000..1525ce3953e
--- /dev/null
+++ b/extensions/css/server/src/stylesheetCache.ts
@@ -0,0 +1,84 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import {TextDocument} from 'vscode-languageserver';
+import {Stylesheet} from './parser/cssNodes';
+
+export interface StylesheetCache {
+	getStylesheet(document: TextDocument): Stylesheet;
+	onDocumentRemoved(document: TextDocument): void;
+	dispose(): void;
+}
+
+export function getStylesheetCache(maxEntries: number, cleanupIntervalTimeInSec: number, parseStylesheet: (document: TextDocument) => Stylesheet) : StylesheetCache {
+	let styleSheets: { [uri:string]: {version:number, languageId: string, cTime: number, stylesheet: Stylesheet}} = {};
+	let nStyleSheets = 0;
+
+	let cleanupInterval = void 0;
+	if (cleanupIntervalTimeInSec > 0) {
+		cleanupInterval = setInterval(() => {
+			let cutoffTime = Date.now() - cleanupIntervalTimeInSec * 1000;
+			let uris = Object.keys(styleSheets);
+			for (let uri of uris) {
+				let stylesheetInfo = styleSheets[uri];
+				if (stylesheetInfo.cTime < cutoffTime) {
+					delete styleSheets[uri];
+					nStyleSheets--;
+				}
+			}
+		}, cleanupIntervalTimeInSec * 1000);
+	}
+
+	return {
+		getStylesheet(document: TextDocument) {
+			let version = document.version;
+			let languageId = document.languageId;
+			let stylesheetInfo = styleSheets[document.uri];
+			if (stylesheetInfo && stylesheetInfo.version === version && stylesheetInfo.languageId === languageId) {
+				stylesheetInfo.cTime = Date.now();
+				return stylesheetInfo.stylesheet;
+			}
+			let stylesheet = parseStylesheet(document);
+			styleSheets[document.uri] = { stylesheet, version, languageId, cTime: Date.now()};
+			if (!stylesheetInfo) {
+				nStyleSheets++;
+			}
+
+			if (nStyleSheets === maxEntries) {
+				let oldestTime = Number.MAX_VALUE;
+				let oldestUri = null;
+				for (let uri in styleSheets) {
+					let stylesheetInfo = styleSheets[uri];
+					if (stylesheetInfo.cTime < oldestTime) {
+						oldestUri = uri;
+						oldestTime = stylesheetInfo.cTime;
+					}
+				}
+				if (oldestUri) {
+					delete styleSheets[oldestUri];
+					nStyleSheets--;
+				}
+			}
+			return stylesheet;
+
+		},
+		onDocumentRemoved(document: TextDocument) {
+			let uri = document.uri;
+			if (styleSheets[uri]) {
+				delete styleSheets[uri];
+				nStyleSheets--;
+			}
+		},
+		dispose() {
+			if (typeof cleanupInterval !== 'undefined') {
+				clearInterval(cleanupInterval);
+				cleanupInterval = void 0;
+				styleSheets = {};
+				nStyleSheets = 0;
+			}
+		}
+	};
+}
\ No newline at end of file