The paper looks at the concept of ROI (Return On Investment) in the context of libraries. In light of the dynamic environment, challenging financial pressures and increasing need for accountability have in all forced libraries to prove their worth in terms of outcomes, impact and returns. The paper draws upon various studies and approaches in dealing with this relevant and important topical theme. The paper focuses on academic libraries and concludes that ROI of each library will be different depending on the settings in which it exists. It is important to study the settings and then clearly envisage the measures of returnes of each library.