The importance of adequate complementary feeding of infants is increasingly acknowledged. Little is known of the actual complementary feeding practices in Switzerland.; To report the prevalence of adequate timing of complementary feeding, comparing the compliance to Swiss and World Health Organization (WHO) guidelines, and to investigate factors influencing infant complementary feeding.; In 2003 a cross-sectional study was conducted of mother-and-infant pairs in Switzerland. The mothers, randomly chosen by local community mother-and-child health services, completed a 24-h dietary recall questionnaire and reported the infant's age at the first introduction of various foods. Descriptive analysis, group testing and regression analysis of data collected were conducted.; Introduction of solids mainly occurred between the 5th and 6th months. Five per cent of the mothers introduced complementary food before the age of 4 mo. The main influencing factors for infant feeding were maternal age, language regions, mother's BMI and smoking status, the presence of siblings, and an allergic predisposition of the infant.; The timing of the introduction of complementary foods meets with Swiss guidelines. WHO recommendations, however, are not met. This may be due to a misunderstanding of the Swiss Paediatric Association's age-range recommendations or insufficient promotion of the WHO recommendations.