Social Media (SM) provides a range of possibilities for libraries to provide services out from traditional ways and means as modern life has been influenced greatly and massively by the internet. Owing to the amazing advancement of services given through the internet, libraries and information centers have to change and perform efficiently to convene the information needs of modern users. Libraries must use the modern SM tools to enhance and thrive in this age of the internet. Currently, libraries are adopting these tools in their services to satisfy the information and research needs of the users. SM applications in libraries drive to convene the growing and varying prospects of library clients. This paper aims to investigate the use of SM to enhance library effectiveness in Pakistani libraries. The study is based on a survey that was administered through survey monkey. The data of 71 filled questionnaires were analyzed using the Statistical Package for Social Sciences. Results show that 73.2% of respondents started using social media after 2008, and the top users are university libraries (53.52%). 76.1% using Facebook, but 56.3% believe in the usefulness of blogs/blogging. Professional networking (74.6%) is the main purpose of using SM, followed by the promotion of library services (69%). Three main challenges in using SM at libraries are 1) technical problems, 2) restrictions on using social media at the office; and 3) low internet connection.