Objective: Increasing drug expenditures are a major concern in health care systems worldwide. Additionally, in developing countries such as Brazil, guaranteeing expanded drug access within a constrained public healthcare budget is a pivotal challenge. Our objective was to characterize and quantify drug consumption and its economic burden in the primary care setting in the city of Fortaleza, Brazil. Methods: The drug acquisition database from the Municipality of Fortaleza, Brazil was surveyed. The database comprehends daily drug acquisitions funded by the Brazilian Public Health System, which provides free formulary-listed drugs to the public-managed primary health care service of Fortaleza, a 2.3 million people city. A complete dataset of the year 2006 was used in the analysis. Drugs were categorized according to the Anatomical Therapeutic Chemical Classification (ATC, WHO) coding and their consumption was reported as Defined Daily Dose (DDD) per 1000 inhabitants/day. Individual drug acquisition costs were calculated and summed to project the economic burden of drugs in 2006. Results: The estimated economic burden of drugs in the publicly-administered primary health care in Fortaleza for the year 2006 was R$10 million (approximately US$5.5 million). Drugs comprised only 1.53% of total healthcare expenditures. The therapeutical class with highest expenditure was antibiotics (26.2% of total drug expenditures; mainly represented by beta-lactamics/penicillins), followed by antihypertensives (15.3%; mainly represented by renin-angiotensin drugs). Most consumed drugs and strengths were captopril 25mg (22.7 DDDs/1000 inhabitants/day), followed by hydrochlorotiazide 50mg (16.1) and acetil salicilic acid 0.1mg (8.7). Drugs with highest cost/DDD were penicillin benzathine 600,000U (R$8.00), followed by norethisterone 0.35mg (DDD low preparation 0.65mg; R$4.77) and penicillin benzathine 1,200,000U (R$4.42). Conclusion: Drugs used to treat most prevalent cardiovascular chronic diseases were the most consumed in Fortaleza. However, higher expenditures lie within drugs for treating infections. Research should study specific determinants of drug consumption and expenditures in public-health care system in Fortaleza, Brazil.