OBJECTIVES: To assess the impact of drug policy on improving access to essential medicines in Delhi  METHODS: The quantity of drugs procured from the Essential Drugs List (EDL) and outside the EDL; money spent on these; changes in stock out days for the key drugs. The implementation strategy includes elements of drug policy like use of EDL & STG, improved procurement system, training on drugs management & rational use of drugs. Retrospective data collected from stock registers. The data for two years before (1993-1994, 1994-1995) and two years after (2000-2001, 2001-2002) the drug policy was assessed. Data collected from two large public sector hospitals in Delhi that serve a large section of the population through convenient purposive sampling method.  RESULTS: After the implementation of the drug policy, the availability of drugs increased by 25% in the large and 98% in the medium hospital. The drugs procured from the EDL increased from 62% to 78% in the large and 74% to 87% in the medium hospital. Of the total expenditure, the money spent on essential drugs increased from 73% to 85% in the large and 87% to 93% in the medium hospital, whereas money spent on nonessential drugs decreased from 27% to 15% in the large and 13% to 7% in the medium hospital. The average number of stock out days for key dugs decreased from 33 to 16 days in the large and from 143 days to 33 days in the medium hospital. The utilization pattern of health services by patients increased by 8% in the large and by 35% in the medium hospital.  CONCLUSIONS: The implementation of the drug policy in the state of Delhi increased availability of essential drugs. This kind of intervention can serve as a model for improving access to medicines by implementing an effective drug.