diff --git a/README.rdoc b/README.rdoc
index 3ed373d..2c28687 100644
--- a/README.rdoc
+++ b/README.rdoc
@@ -47,6 +47,21 @@ For shorten requests, each short URL for an authenticated user is unique, and th
 
 Go to http://goo.gl to see URL statistics.
 
+=== Shorten without generating new short URL (if exists long_url in history)
+
+  client = Googl.client('user@gmail.com', 'my_valid_password')
+  url = client.shorten('https://github.com/zigotto/googl')
+  url.short_url
+  => http://goo.gl/DWDfi
+
+  url = client.shorten('https://github.com/zigotto/googl')
+  url.short_url
+  => http://goo.gl/Oh48S
+
+  url = client.shorten('https://github.com/zigotto/googl', unique: true)
+  url.short_url
+  => http://goo.gl/Oh48S
+
 === OAuth
 
 Google supports three flows of OAuth 2.0
diff --git a/lib/googl.rb b/lib/googl.rb
index e31ab12..4dab122 100644
--- a/lib/googl.rb
+++ b/lib/googl.rb
@@ -23,9 +23,9 @@ module Googl
   #   url.short_url
   #   => "http://goo.gl/ump4S"
   #
-  def shorten(url=nil)
+  def shorten(url=nil, options = {})
     raise ArgumentError.new("URL to shorten is required") if url.nil? || url.strip.empty?
-    Googl::Shorten.new(url)
+    Googl::Shorten.new(url, options)
   end
 
   # Expands a short URL or gets creation time and analytics
@@ -101,8 +101,12 @@ def expand(url=nil, options={})
   #
   # Go to http://goo.gl to see URL statistics.
   #
-  def client(email, passwd)
-    Googl::ClientLogin.new(email, passwd)
+  def client(email = nil, passwd = nil)
+    unless(email.nil? && passwd.nil?)
+      @client_instance = Googl::ClientLogin.new(email, passwd)
+    end
+
+    @client_instance
   end
 
   # OAuth 2.0
diff --git a/lib/googl/client_login.rb b/lib/googl/client_login.rb
index 193c348..255603c 100644
--- a/lib/googl/client_login.rb
+++ b/lib/googl/client_login.rb
@@ -24,8 +24,8 @@ def initialize(email, passwd)
     #
     # See Googl.client
     #
-    def shorten(url)
-      Googl.shorten(url)
+    def shorten(url, options = {})
+      Googl.shorten(url, options)
     end
 
     # Gets a user's history of shortened URLs. (Authenticated)
diff --git a/lib/googl/shorten.rb b/lib/googl/shorten.rb
index 5227e81..3a42f64 100644
--- a/lib/googl/shorten.rb
+++ b/lib/googl/shorten.rb
@@ -8,8 +8,31 @@ class Shorten < Base
 
     # Creates a new short URL, see Googl.shorten
     #
-    def initialize(long_url)
+    def initialize(long_url, args = {})
+      args = {:unique => false}.merge(args) 
       modify_headers('Content-Type' => 'application/json')
+ 
+      # if long_url exists in history
+      # return the related short_url
+      if args[:unique] && !Googl.client.nil?
+        to_check = URI(long_url)
+        to_check.scheme ||= 'http'
+        to_check.path += '/' if(to_check.path[-1] != '/')
+        Googl.client.history.items.each do |item|
+          uri_from_history = URI(item.long_url)
+
+          if(to_check.scheme == uri_from_history.scheme && 
+             to_check.host == uri_from_history.host && 
+             to_check.path == uri_from_history.path && 
+             to_check.query == uri_from_history.query)
+            self.short_url  = item.label
+            self.long_url   = item.long_url
+            return self
+          end
+
+        end
+      end
+
       options = {"longUrl" => long_url}.to_json
       resp = post(API_URL, :body => options)
       if resp.code == 200
diff --git a/spec/fixtures/history.json b/spec/fixtures/history.json
index 794ceaa..45392c8 100644
--- a/spec/fixtures/history.json
+++ b/spec/fixtures/history.json
@@ -147,6 +147,13 @@ Transfer-Encoding: chunked
    "longUrl": "http://jlopes.zigotto.com.br/",
    "status": "OK",
    "created": "2010-10-01T13:26:04.029+00:00"
+  },
+  {
+   "kind": "urlshortener#url",
+   "id": "http://goo.gl/ice1",
+   "longUrl": "http://www.ice.com/",
+   "status": "OK",
+   "created": "2014-01-13T14:52:30.401+00:00"
   }
  ]
 }
diff --git a/spec/fixtures/shorten_ice1.json b/spec/fixtures/shorten_ice1.json
new file mode 100644
index 0000000..5c1847b
--- /dev/null
+++ b/spec/fixtures/shorten_ice1.json
@@ -0,0 +1,18 @@
+HTTP/1.1 200 OK
+ETag: "EEZ1AD443JkEgW3KJFaymzTd26A/41aG_KwuemZSq8rrtXp-EsY0Iuk"
+Cache-Control: no-cache, no-store, max-age=0, must-revalidate
+Pragma: no-cache
+Expires: Fri, 01 Jan 1990 00:00:00 GMT
+Date: Thu, 13 Jan 2011 13:07:26 GMT
+Content-Type: application/json; charset=UTF-8
+X-Content-Type-Options: nosniff
+X-Frame-Options: SAMEORIGIN
+X-XSS-Protection: 1; mode=block
+Server: GSE
+Transfer-Encoding: chunked
+
+{
+ "kind": "urlshortener#url",
+ "id": "http://goo.gl/ice1",
+ "longUrl": "http://www.ice.com/"
+}
diff --git a/spec/fixtures/shorten_ice2.json b/spec/fixtures/shorten_ice2.json
new file mode 100644
index 0000000..1b3712d
--- /dev/null
+++ b/spec/fixtures/shorten_ice2.json
@@ -0,0 +1,18 @@
+HTTP/1.1 200 OK
+ETag: "EEZ1AD443JkEgW3KJFaymzTd26A/41aG_KwuemZSq8rrtXp-EsY0Iuk"
+Cache-Control: no-cache, no-store, max-age=0, must-revalidate
+Pragma: no-cache
+Expires: Fri, 01 Jan 1990 00:00:00 GMT
+Date: Thu, 13 Jan 2011 13:07:26 GMT
+Content-Type: application/json; charset=UTF-8
+X-Content-Type-Options: nosniff
+X-Frame-Options: SAMEORIGIN
+X-XSS-Protection: 1; mode=block
+Server: GSE
+Transfer-Encoding: chunked
+
+{
+ "kind": "urlshortener#url",
+ "id": "http://goo.gl/ice2",
+ "longUrl": "http://www.ice.com/"
+}
diff --git a/spec/googl/client_spec.rb b/spec/googl/client_spec.rb
index 0d4e341..f56bd56 100644
--- a/spec/googl/client_spec.rb
+++ b/spec/googl/client_spec.rb
@@ -46,6 +46,26 @@
       it "should return a short URL" do
         subject.short_url.start_with?("http://goo.gl/").should be_true
       end
+
+      context "without unique parameter" do
+
+        let(:first) { @client.shorten('http://www.ice.com')}
+        let(:second) { @client.shorten('http://www.ice.com')}
+
+        it "should generate new short URL" do
+          first.short_url.should_not eql(second.short_url)
+        end
+      end     
+
+      context "with unique parameter" do
+
+        let(:first) { @client.shorten('http://www.ice.com', unique: true)}
+        let(:second) { @client.shorten('http://www.ice.com', unique: true)}
+
+        it "should get short URL from history" do
+          first.short_url.should eql(second.short_url)
+        end
+      end     
     end
     
   end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 1486f27..634a28b 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -76,6 +76,23 @@ def fake_urls?(status)
            :headers => {'Authorization'=>'GoogleLogin auth=DQAAAK8AAAC9ahL-o7g', 'Content-Type'=>'application/json'}).
            to_return(load_fixture('shorten_authenticated.json'))
 
+    # simulate random url generation
+    $COUNTER = true 
+    params = "{\"longUrl\":\"http://www.ice.com\"}"
+    stub_request(:post, url_shorten).
+      with(:body => params, 
+        :headers => {'Authorization'=>'GoogleLogin auth=DQAAAK8AAAC9ahL-o7g', 'Content-Type'=>'application/json'}).
+        to_return(lambda do |request|
+          if $COUNTER
+            $COUNTER = !$COUNTER
+            load_fixture('shorten_ice1.json')
+          else
+            $COUNTER = !$COUNTER
+            load_fixture('shorten_ice2.json')
+          end
+        end
+        )
+
     # History for ClientLogin
     stub_request(:get, "https://www.googleapis.com/urlshortener/v1/url/history").
       with(:headers => {'Authorization'=>'GoogleLogin auth=DQAAAK8AAAC9ahL-o7g'}).