The objective of this study was to assess the quality of the data included in patients' personal histories and to prepare an indicator of the continuity of health care between episodes of illness based on the information contained in these records. The study was descriptive. Public health specialists from the Department of Preventive Medicine of the University of Granada, Spain, participated in the design and analysis, and the field work was carried out by specialists from family and community medicine from the Zaidín-Sur Health Center of Granada, where the research was conducted in April to December 1989. For the study, 1581 personal histories were analyzed. The most complete records were those having to do with personal background (37% of the personal histories evaluated) and the most complete histories were those of pediatric patients, women, and persons who participated in programs organized by the health center. The degree of completeness of the records was low. Based on the indicator developed, only 16% of the histories at the Center contained sufficient information to allow continuity of care. It is recommended that simple records systems be created and that primary care physicians be educated in the collection of essential data.