diff --git a/lib/builtins/map.js b/lib/builtins/map.js
index d652c40..d95da21 100644
--- a/lib/builtins/map.js
+++ b/lib/builtins/map.js
@@ -60,23 +60,26 @@ function map(inputdir, outputdir, options) {
 
 				// Otherwise, we queue up a transformation
 				return queue.add(function (fulfil, reject) {
-					return sander.readFile(src).then(String).then(function (data) {
+					// Create context object - this will be passed to transformers
+					var context = {
+						log: _this.log,
+						env: config['default'].env,
+						src: src, dest: dest, filename: filename
+					};
+
+					var transformOptions = assign['default']({}, options.fn.defaults, options.userOptions);
+
+					delete transformOptions.accept;
+					delete transformOptions.ext;
+
+					return sander.readFile(src).then(function (buffer) {
+						return buffer.toString(transformOptions.sourceEncoding);
+					}).then(function (data) {
 						var result, code, map, mappath;
 
 						if (_this.aborted) return;
 
 						try {
-							// Create context object - this will be passed to transformers
-							var context = {
-								log: _this.log,
-								env: config['default'].env,
-								src: src, dest: dest, filename: filename
-							};
-
-							var transformOptions = assign['default']({}, options.fn.defaults, options.userOptions);
-
-							delete transformOptions.accept;
-							delete transformOptions.ext;
 							result = options.fn.call(context, data, transformOptions);
 						} catch (e) {
 							var err = createTransformError(e, src, filename, _this.node);
diff --git a/src/builtins/map.js b/src/builtins/map.js
index 5798efc..8ce00ee 100644
--- a/src/builtins/map.js
+++ b/src/builtins/map.js
@@ -53,23 +53,24 @@ export default function map ( inputdir, outputdir, options ) {
 
 				// Otherwise, we queue up a transformation
 				return queue.add( ( fulfil, reject ) => {
-					return readFile( src ).then( String ).then( data => {
+					// Create context object - this will be passed to transformers
+					let context = {
+						log: this.log,
+						env: config.env,
+						src, dest, filename
+					};
+
+					let transformOptions = assign( {}, options.fn.defaults, options.userOptions );
+
+					delete transformOptions.accept;
+					delete transformOptions.ext;
+
+					return readFile( src ).then( buffer => buffer.toString( transformOptions.sourceEncoding ) ).then( data => {
 						var result, code, map, mappath;
 
 						if ( this.aborted ) return;
 
 						try {
-							// Create context object - this will be passed to transformers
-							let context = {
-								log: this.log,
-								env: config.env,
-								src, dest, filename
-							};
-
-							let transformOptions = assign( {}, options.fn.defaults, options.userOptions );
-
-							delete transformOptions.accept;
-							delete transformOptions.ext;
 							result = options.fn.call( context, data, transformOptions );
 						} catch ( e ) {
 							let err = createTransformError( e, src, filename, this.node );
diff --git a/test/scenarios.js b/test/scenarios.js
index 26fe49a..b9b9d9f 100644
--- a/test/scenarios.js
+++ b/test/scenarios.js
@@ -443,6 +443,35 @@ module.exports = function () {
 				});
 			});
 		});
+
+		it( 'should use the specified encoding when reading files', function () {
+			var source = gobble( 'tmp/foo' ), count = 0, foundBar = false;
+
+			function plugin ( input, options ) {
+				count++;
+
+				if(this.filename === 'bar.md') {
+					foundBar = true;
+
+					assert.equal(
+						new Buffer( input, 'base64' ).toString('utf8').trim(),
+						'bar: this is some text'
+					);
+				}
+
+				return input.toString( 'base64' );
+			}
+			plugin.defaults = {sourceEncoding: 'base64'};
+
+			task = source.transform( plugin ).build({
+				dest: 'tmp/output'
+			});
+
+			return task.then( function () {
+				assert.equal( count, 3 );
+				assert( foundBar );
+			});
+		});
 	});