diff --git a/src/main/options.js b/src/main/options.js
index d285bfe7c..da786dbd5 100644
--- a/src/main/options.js
+++ b/src/main/options.js
@@ -26,7 +26,8 @@ function normalize(options, opts) {
   const supportOptions = getSupportInfo(null, {
     plugins,
     pluginsLoaded: true,
-    showUnreleased: true
+    showUnreleased: true,
+    showDeprecated: true
   }).options;
   const defaults = supportOptions.reduce(
     (reduced, optionInfo) =>
@@ -49,10 +50,20 @@ function normalize(options, opts) {
     }
   }
 
-  const parser = resolveParser(rawOptions);
+  const parser = resolveParser(
+    !rawOptions.parser
+      ? rawOptions
+      : // handle deprecated parsers
+        normalizer.normalizeApiOptions(
+          rawOptions,
+          [supportOptions.find(x => x.name === "parser")],
+          { passThrough: true, logger: false }
+        )
+  );
   rawOptions.astFormat = parser.astFormat;
   rawOptions.locEnd = parser.locEnd;
   rawOptions.locStart = parser.locStart;
+
   const plugin = getPlugin(rawOptions);
   rawOptions.printer = plugin.printers[rawOptions.astFormat];
 
diff --git a/tests_integration/__tests__/__snapshots__/deprecated-parser.js.snap b/tests_integration/__tests__/__snapshots__/deprecated-parser.js.snap
new file mode 100644
index 000000000..beb62c7a8
--- /dev/null
+++ b/tests_integration/__tests__/__snapshots__/deprecated-parser.js.snap
@@ -0,0 +1,6 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`API format with deprecated parser should work 1`] = `
+"\`{ \\"parser\\": \\"postcss\\" }\` is deprecated. Prettier now treats it as \`{ \\"parser\\": \\"css\\" }\`.
+"
+`;
diff --git a/tests_integration/__tests__/deprecated-parser.js b/tests_integration/__tests__/deprecated-parser.js
new file mode 100644
index 000000000..96e111fb3
--- /dev/null
+++ b/tests_integration/__tests__/deprecated-parser.js
@@ -0,0 +1,26 @@
+"use strict";
+
+const prettier = require("../../tests_config/require_prettier");
+
+let warnings = "";
+
+beforeAll(() => {
+  jest
+    .spyOn(console, "warn")
+    .mockImplementation(text => (warnings += text + "\n"));
+});
+
+beforeEach(() => {
+  warnings = "";
+});
+
+afterAll(() => {
+  jest.restoreAllMocks();
+});
+
+test("API format with deprecated parser should work", () => {
+  expect(() =>
+    prettier.format("body { color: #131313; }", { parser: "postcss" })
+  ).not.toThrowError();
+  expect(warnings).toMatchSnapshot();
+});