diff --git a/README.md b/README.md
index 170277f0..33ef5b5e 100644
--- a/README.md
+++ b/README.md
@@ -302,6 +302,19 @@ const sellParams = {
 authedClient.sell(sellParams, callback);
 ```
 
+* [`placeOrder`](https://docs.gdax.com/#place-a-new-order)
+
+```js
+// Buy 1 LTC @ 75 USD
+const params = {
+  'side': 'buy',
+  'price': '75.00', // USD
+  'size': '1', // LTC
+  'product_id': 'LTC-USD',
+};
+authedClient.placeOrder(params, callback);
+```
+
 * [`cancelOrder`](https://docs.gdax.com/#cancel-an-order)
 
 ```js
diff --git a/index.d.ts b/index.d.ts
index 1dbaa98b..f0454708 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -193,6 +193,9 @@ declare module 'gdax' {
         sell(params: OrderParams, callback: callback<OrderResult>);
         sell(params: OrderParams): Promise<OrderResult>;
 
+        placeOrder(params: OrderParams, callback: callback<OrderResult>);
+        placeOrder(params: OrderParams): Promise<OrderResult>;
+
         cancelOrder(orderID, callback: callback<any>);
         cancelOrder(orderID): Promise<any>;
 
diff --git a/lib/clients/authenticated.js b/lib/clients/authenticated.js
index e2645fe6..59c2cde8 100644
--- a/lib/clients/authenticated.js
+++ b/lib/clients/authenticated.js
@@ -81,7 +81,7 @@ class AuthenticatedClient extends PublicClient {
     return this.get(['accounts', accountID, 'holds'], { qs: args }, callback);
   }
 
-  _placeOrder(params, callback) {
+  placeOrder(params, callback) {
     let requiredParams = ['side', 'product_id'];
     let needsSize = params.type !== 'market' && params.type !== 'stop';
 
@@ -95,17 +95,21 @@ class AuthenticatedClient extends PublicClient {
       throw new Error('`opts` must include either `size` or `funds`');
     }
 
+    if (params.side !== 'buy' && params.side !== 'sell') {
+      throw new Error('`side` must be `buy` or `sell`');
+    }
+
     return this.post(['orders'], { body: params }, callback);
   }
 
   buy(params, callback) {
     params.side = 'buy';
-    return this._placeOrder(params, callback);
+    return this.placeOrder(params, callback);
   }
 
   sell(params, callback) {
     params.side = 'sell';
-    return this._placeOrder(params, callback);
+    return this.placeOrder(params, callback);
   }
 
   getTrailingVolume(callback) {
diff --git a/tests/authenticated.spec.js b/tests/authenticated.spec.js
index d063cfed..e1589dbc 100644
--- a/tests/authenticated.spec.js
+++ b/tests/authenticated.spec.js
@@ -213,6 +213,33 @@ suite('AuthenticatedClient', () => {
       .catch(err => assert.ifError(err) || assert.fail());
   });
 
+  test('.placeOrder()', done => {
+    const order = {
+      side: 'buy',
+      funds: '20.00',
+      product_id: 'ETH-USD',
+      type: 'market',
+    };
+
+    const expectedOrder = order;
+
+    const expectedResponse = {
+      id: '0428b97b-bec1-429e-a94c-59992926778d',
+    };
+
+    nock(EXCHANGE_API_URL)
+      .post('/orders', expectedOrder)
+      .reply(200, expectedResponse);
+
+    authClient.placeOrder(order, (err, resp, data) => {
+      assert.ifError(err);
+      assert.deepEqual(data, expectedResponse);
+
+      nock.cleanAll();
+      done();
+    });
+  });
+
   test('.buy()', done => {
     const order = {
       size: '10',