OBJECTIVES: To highlight the importance of considering both age and gender of users (population (pop) with any prescription) if analyzing pharmaceutical expenditure. METHODS: All primary health care prescriptions (2003) have been considered (95 million prescriptions; 4.2 million users; 1,237 million €). Indicators analyzed: prescriptions per user (P/U), cost per prescription (C/P) and cost per user (C/U), all from administration viewpoint. Risk of consuming (U/Pop) has been also calculated according to age and gender. RESULTS: Global: C/U: €291.9; P/U:22.4; C/P: €13.0. Men present prescriptions more expensive (+€1.5), but women are more expensive (€305.6 vs €275.4) because on average they demand 4.8 prescriptions more than men .P/U grows exponentially (R2=0.929) until 89y.o.(63.4). Min:4.3(10y.o.). C/P varies considerably until 28y.o. (avg:€10.0; Pearson v.c:32.1). Prescriptions of growth hormone increase the C/P a 83% among 12-16y.o. Since 29y.o. C/P stabilizes (avg:€12.9; Pearson v.c.:8.6) presenting an upward trend at ages close to retirement age (chronic illnesses and copayment). C/U behaves exponentially until 88y.o. (R2= 0.962). At 88y.o. C/U is 3 times higher than global average and 28.5 higher than at 5y.o. Since 17y.o., women consume more medicines than men, but men present prescriptions more expensive than women so there are alternations in C/U. U/Pop at 70y.o. is 1.84 times higher than at 30y.o.(prob.0.90 vs 0.49), and the difference in C/U is €569. For equal ages, there are also differences in U/Pop between primary health care teams (PHCTs) because of, for example, other socio-economic and geographical variables. CONCLUSIONS: It's important to include age and gender of users in comparative analysis between PHCTs in order to consider differences in the population pyramid and in utilization levels. BenchMarking activity between PHCTs is being carried out monthly with these three standardized indicators. These reports allow to locate inefficiency with more accuracy and to apply measures more effective.