OBJECTIVES Wal-Mart Stores (WMS) was the first pharmacy to offer the Generic Drug Discount Program (GDDP) in 2006. The objective of this study was to compare GDDPs offered by large chain pharmacies in the United States. METHODS A prospective cross-sectional field study was conducted by obtaining data (March 2008 to November 2008) on GDDPs offered using a combination of telephone and face to face interview technique. Data obtained from the pharmacy included GDDPs offered, type of GDDP (patient cost for 30/90 day supply {DS}), number and type of drugs covered. Data coded in an excel sheet was analyzed by considering the WMS program as a reference to evaluate similarities/differences among GDDPs. Comparison were further performed by matching drugs covered in each GDDP with the top 100 generics (by units) consumed in the US in 2007. RESULTS A total of 22 (of 37) pharmacies offered GDDPs. The patient sharing cost ranged from $3.99 to $9.99 for a 30DS and from $9.99 to $15.99 for a 90DS. Seven GDDPs (31.8%) were similar to WMS program with respect to number of generics covered (300-400), cost for 30DS ($4), and cost for 90 DS ($10). Four GDDPs (18.2%) were identified as not at par with the WMS program, while 10 (45.4%) were identified as superior. The superior GDDPs offered more drugs (>400), while the inferior programs offered the same or less number of drugs at a higher cost ($9.99 for 30DS, and $12.99-$15.99 for 90DS). The GDDPs varied by the number of top 100 drugs covered with 72.7% covering more or same number of top 100 drugs as WMS. CONCLUSIONS GDDPs were different across pharmacies in terms of number and type of generic medications covered, and cost for 30/90 day supply. Patients can save on generic drugs if they make the right choices.