diff --git a/lib/Connection.js b/lib/Connection.js
index af470eb8c..a51c51aa9 100644
--- a/lib/Connection.js
+++ b/lib/Connection.js
@@ -32,6 +32,9 @@ class Connection {
 
   request (params, callback) {
     params.url = resolve(this.host.href, params.path)
+    if (params.querystring != null && params.querystring.length > 0) {
+      params.url += '?' + params.querystring
+    }
     params.agent = this._agent
     debug('Starting a new request', params)
     return makeRequest(params, callback)
diff --git a/lib/Serializer.js b/lib/Serializer.js
index 52125ea29..97516a2c0 100644
--- a/lib/Serializer.js
+++ b/lib/Serializer.js
@@ -1,5 +1,6 @@
 'use strict'
 
+const { stringify } = require('querystring')
 const debug = require('debug')('elasticsearch')
 const { SerializationError, DeserializationError } = require('./errors')
 
@@ -35,6 +36,19 @@ class Serializer {
     }
     return ndjson
   }
+
+  qserialize (object) {
+    debug('qserialize', object)
+    // arrays should be serialized as comma separated list
+    const keys = Object.keys(object)
+    for (var i = 0, len = keys.length; i < len; i++) {
+      var key = keys[i]
+      if (Array.isArray(object[key]) === true) {
+        object[key] = object[key].join(',')
+      }
+    }
+    return stringify(object)
+  }
 }
 
 module.exports = Serializer
diff --git a/lib/Transport.js b/lib/Transport.js
index 6885d143c..420e65767 100644
--- a/lib/Transport.js
+++ b/lib/Transport.js
@@ -42,28 +42,37 @@ class Transport {
 
     // handle json body
     if (params.body != null) {
-      try {
-        params.body = this.serializer.serialize(params.body)
-      } catch (err) {
-        return callback(err)
+      if (typeof params.body !== 'string') {
+        try {
+          params.body = this.serializer.serialize(params.body)
+        } catch (err) {
+          return callback(err)
+        }
       }
       params.headers = params.headers || {}
       params.headers['Content-Type'] = 'application/json'
       params.headers['Content-Length'] = '' + Buffer.byteLength(params.body)
     // handle ndjson body
     } else if (params.bulkBody != null) {
-      try {
-        params.body = this.serializer.ndserialize(params.bulkBody)
-      } catch (err) {
-        return callback(err)
+      if (typeof params.bulkBody !== 'string') {
+        try {
+          params.body = this.serializer.ndserialize(params.bulkBody)
+        } catch (err) {
+          return callback(err)
+        }
+      } else {
+        params.body = params.bulkBody
       }
       params.headers = params.headers || {}
       params.headers['Content-Type'] = 'application/x-ndjson'
       params.headers['Content-Length'] = '' + Buffer.byteLength(params.body)
     }
 
+    // serializes the querystring
+    params.querystring = this.serializer.qserialize(params.querystring)
     params.timeout = params.timeout || this.requestTimeout
     this.emit('request', params)
+
     const request = connection.request(params, (err, response) => {
       if (err != null) {
         this.connectionPool.markDead(connection)