OBJECTIVES To identify the population seen at general/family medical practices and quantity the episodes of illnesses attended, in function of the demographic context. DESIGN An observational, prospective study based on a year-long record. SETTING 43 practices spread over 10 autonomous communities. INTERVENTIONS Identification, sex and date of birth of each patient attended, the type of episode, health problem and date of their first consultation, were all recorded. Standardisation by the indirect method was used to compare morbidity rates. RESULTS 2.39 episodes per person seen were attended in rural areas, 2.42 in urban ones, and 2.45 in mixed areas. The rural context had rates below 15% of the standard rate for neoplasias, endocrine diseases, neurological illness and additional categories; and over 15% for digestive tract diseases, traumas and side-effects. The urban context had higher rates for neoplasias, endocrine, blood and neurological diseases, and additional categories; and lower for respiratory system illnesses. In the mixed areas, rates were higher for contagious, neurological, respiratory system and congenital diseases. CONCLUSIONS The morbidity attended varies in function of context. Some differences could be due to age distribution (younger in the mixed areas) or accidents (greater in rural areas). Others could be affected by use or problem-solving criteria varying according to the demographic context.