The use of antibiotics depends on cultural and socioeconomic factors, physician's characteristics as well as on microbiological considerations. Aim of our study was to asses antibiotic prescription among preschool children in primary health care in Croatia in relation to socioeconomic factors, symptoms and diagnoses, and type of health care provider. Retrospective longitudinal survey was conducted in 7 teaching primary health care offices in the Croatian capital of Zagreb during 2004, among 1700 preschool children. Antibiotics were prescribed to 611 (46%) children. Significantly more antibiotics were prescribed to boys (66.7%, P = 0.024) and to children whose parents had lower educational level. Most frequently antibiotics were prescribed for the symptoms such as fever (32%), cough (32.5%), nasal discharge (12%), and for the diagnoses such as respiratory diseases (J00-J99) (40%), infectious and parasitic diseases (A00-A99) (31%), and diseases of the middle ear and mastoid (H60-H95) (15%). Logistic regression analyses also predicted correlation of antibiotic prescriptions with socioeconomic factors, symptoms and diagnoses and health care of pediatrician. Prescription of antibiotics for preschool children in primary health care in Croatia related to socioeconomic factors, type of health care provider, certain symptoms and diagnosis groups which should be taken into account when assessing and planning primary health care for preschool children.