diff --git a/index.js b/index.js
index a3d67a6..e4c21e6 100644
--- a/index.js
+++ b/index.js
@@ -3,7 +3,7 @@
 const fp = require('fastify-plugin')
 var pg = require('pg')
 
-function transactionUtil (pool, query, values, cb) {
+function transactionUtil (pool, fn, cb) {
   pool.connect((err, client, done) => {
     if (err) return cb(err)
 
@@ -18,9 +18,8 @@ function transactionUtil (pool, query, values, cb) {
 
     client.query('BEGIN', (err) => {
       if (shouldAbort(err)) return cb(err)
-      client.query(query, values, (err, res) => {
-        if (shouldAbort(err)) return cb(err)
 
+      fn(client).then(res => {
         client.query('COMMIT', (err) => {
           done()
           if (err) {
@@ -28,22 +27,24 @@ function transactionUtil (pool, query, values, cb) {
           }
           return cb(null, res)
         })
+      }).catch(err => {
+        if (shouldAbort(err)) return cb(err)
       })
     })
   })
 }
 
-function transact (query, values, cb) {
+function transact (fn, cb) {
   if (!cb) {
     return new Promise((resolve, reject) => {
-      transactionUtil(this, query, values, function (err, res) {
+      transactionUtil(this, fn, function (err, res) {
         if (err) { return reject(err) }
         return resolve(res)
       })
     })
   }
 
-  return transactionUtil(this, query, values, cb)
+  return transactionUtil(this, fn, cb)
 }
 
 function fastifyPostgres (fastify, options, next) {
diff --git a/test.js b/test.js
index 44f306c..0f4bc3d 100644
--- a/test.js
+++ b/test.js
@@ -268,9 +268,9 @@ test('fastify.pg.test use transact util with promise', t => {
     t.error(err)
     fastify.pg.test
       .query('CREATE TABLE users(id serial PRIMARY KEY, username VARCHAR (50) NOT NULL)')
-      .then(result => {
+      .then(() => {
         fastify.pg.test
-          .transact('INSERT INTO users(username) VALUES($1) RETURNING id', ['brianc'])
+          .transact(client => { return client.query('INSERT INTO users(username) VALUES($1) RETURNING id', ['brianc']) })
           .then(result => {
             t.ok(result.rows[0].id === 1)
             fastify.pg.test
@@ -308,9 +308,9 @@ test('fastify.pg.test use transact util with callback', t => {
     t.error(err)
     fastify.pg.test
       .query('CREATE TABLE users2(id serial PRIMARY KEY, username VARCHAR (50) NOT NULL)')
-      .then(function () {
+      .then(() => {
         fastify.pg.test
-          .transact('INSERT INTO users2(username) VALUES($1) RETURNING id', ['brianc'], function (err, res) {
+          .transact(client => { return client.query('INSERT INTO users2(username) VALUES($1) RETURNING id', ['brianc']) }, function (err, res) {
             if (err) {
               t.fail(err)
               fastify.close()