Segmentation o f Prescribers classifies prescribers into different groups which enables the pharmaceutical marketers to understand the markets from prescriber's viewpoint. For marketing managers a clear reading ofprescriber s needs, behavior, perceptions and prescribing processes is required to formulate desired marketing strategies. Understanding customers is more important than ever in today's competitive economy, where declining customer loyalty and high customer turnover continue to erode profit margins. Without accurate, verifiable segmentation o f customers with respect to value, strategic decision makers cannot get the information they need to evaluate and execute strategies fo r improving customer profitability and the efficiency o f marketing campaigns. This paper is an attempt to study the different basis used by prescription drug marketers and professionals to segment the prescribers. Furthermore, to suggest the best segmentation strategy so as to improve the performance o f pharmaceutical companies.