diff --git a/index.js b/index.js
index ce3d024..455cc85 100644
--- a/index.js
+++ b/index.js
@@ -164,6 +164,9 @@ Vector.prototype.getTile = function(z, x, y, callback) {
             .digest('hex'));
         headers['Last-Modified'] = new Date(head && head['Last-Modified'] || 0).toUTCString();
 
+        // Passthrough backend expires header if present.
+        if (head['Expires']||head['expires']) headers['Expires'] = head['Expires']||head['expires'];
+
         // Return headers for 'headers' format.
         if (format === 'headers') return callback(null, headers, headers);
 
diff --git a/test/fixtures/expires.xml b/test/fixtures/expires.xml
new file mode 100644
index 0000000..e8877c3
--- /dev/null
+++ b/test/fixtures/expires.xml
@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE Map[]>
+<Map srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over" background-color="#ffffff" maximum-extent="-20037508.34,-20037508.34,20037508.34,20037508.34">
+
+<Parameters>
+  <Parameter name="bounds">-180,-85.0511,180,85.0511</Parameter>
+  <Parameter name="center">0,0,2</Parameter>
+  <Parameter name="format">png8:m=h</Parameter>
+  <Parameter name="minzoom">0</Parameter>
+  <Parameter name="maxzoom">8</Parameter>
+  <Parameter name="scale">1</Parameter>
+  <Parameter name="source">test:///expires</Parameter>
+  <Parameter name="name"><![CDATA[test-a]]></Parameter>
+  <Parameter name="interactivity_layer">coastline</Parameter>
+  <Parameter name="interactivity_fields">ScaleRank</Parameter>
+  <Parameter name="json"><![CDATA[{"level1":{"level2":"property"},"scale":2}]]></Parameter>
+</Parameters>
+
+
+<Style name="coastline" filter-mode="first">
+  <Rule>
+    <LineSymbolizer stroke-width="1" stroke="#000000" />
+  </Rule>
+</Style>
+<Layer name="coastline"
+  srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over">
+  <StyleName>coastline</StyleName>
+</Layer>
+
+</Map>
diff --git a/test/test.js b/test/test.js
index b9ab5c2..7d9f831 100644
--- a/test/test.js
+++ b/test/test.js
@@ -16,7 +16,8 @@ var xml = {
     b: fs.readFileSync(path.resolve(__dirname + '/fixtures/b.xml'), 'utf8'),
     c: fs.readFileSync(path.resolve(__dirname + '/fixtures/c.xml'), 'utf8'),
     i: fs.readFileSync(path.resolve(__dirname + '/fixtures/i.xml'), 'utf8'),
-    space: fs.readFileSync(path.resolve(__dirname + '/fixtures/s p a c e/i.xml'), 'utf8')
+    space: fs.readFileSync(path.resolve(__dirname + '/fixtures/s p a c e/i.xml'), 'utf8'),
+    expires: fs.readFileSync(path.resolve(__dirname + '/fixtures/expires.xml'), 'utf8')
 };
 
 test('should fail without backend', function(t) {
@@ -88,6 +89,17 @@ test('should use fallback backend', function(t) {
         t.end();
     });
 });
+test('passes through backend expires header', function(t) {
+    new Vector({ source:'test:///expires', xml: xml.expires }, function(err, source) {
+        t.ifError(err);
+        source.getTile(0, 0, 0, function(err, buffer, headers) {
+            t.ifError(err);
+            t.ok(buffer);
+            t.equal(headers.Expires, 'Wed, 01 Jan 2020 00:00:00 GMT');
+            t.end();
+        });
+    });
+});
 
 var sources = {
     a: new Vector({ backend: new Testsource('a'), xml: xml.a }),
diff --git a/test/testsource.js b/test/testsource.js
index 7cbddc0..b90ab7f 100644
--- a/test/testsource.js
+++ b/test/testsource.js
@@ -67,6 +67,23 @@ var infos = {
                 }
             }
         ]
+    },
+    expires: {
+        minzoom:0,
+        maxzoom:1,
+        vector_layers: [
+            {
+                "id": "coastline",
+                "description": "",
+                "minzoom": 0,
+                "maxzoom": 22,
+                "fields": {
+                    "FeatureCla": "String",
+                    "Note": "String",
+                    "ScaleRank": "Number"
+                }
+            }
+        ]
     }
 };
 var tiles = {
@@ -89,7 +106,12 @@ var tiles = {
         var key = basename.split('.').slice(0,3).join('.');
         memo[key] = fs.readFileSync(path.resolve(path.join(__dirname, 'fixtures', 'gz', basename)));
         return memo;
-    }, {})
+    }, {}),
+    expires: fs.readdirSync(path.resolve(path.join(__dirname, 'fixtures','a'))).reduce(function(memo, basename) {
+        var key = basename.split('.').slice(0,3).join('.');
+        memo[key] = fs.readFileSync(path.resolve(path.join(__dirname, 'fixtures', 'a', basename)));
+        return memo;
+    }, {}),
 };
 
 // Additional error tile fixtures.
@@ -133,6 +155,9 @@ Testsource.prototype.getTile = function(z,x,y,callback) {
         'Content-Type':'application/x-protobuf'
     };
 
+    // Additional headers.
+    if (this.uri === 'expires') headers['expires'] = new Date('2020-01-01').toUTCString();
+
     if (!tiles[this.uri][key]) {
         return callback(new Error('Tile does not exist'));
     } else {