OBJECTIVE: To study factors of importance for infants' use of health and medical care. DESIGN: We studied the medical records of the mother during pregnancy (at the health centre, at the antenatal clinics, and at the department of obstetrics and gynaecology) and of her infant during the first 18 months of life (at the health centre, at the child health clinic, and at the departments of paediatrics and oto-rhino-laryngology). We also interviewed the mother when her infant was 18 months old. SETTING: Teleborg health centre, Växjö, southern Sweden. SUBJECTS: 206 infants and their mothers. MAIN OUTCOME MEASURES: Medical visits, to doctor or district nurse, during the infants' first 18 months of life, and factors of potential importance for those visits. RESULTS: A stepwise linear multiple regression analysis showed that the following factors were of importance for the infant's use of health and medical care: number of mother's visits to the health and medical services during pregnancy, mother being a primipara, and mother being a blue-collar worker. The model (12.98 + 0.52* (no. of mother's visits) + 2.19 (if primipara) + 1.48 (if blue-collar worker)) was able to explain 8.6% of the number of infant's visits. CONCLUSION: The studied factors explained only a minor part of the infants' use of health and medical care.