BACKGROUND: Due to clinical and non-clinical factors, considerable variation exists in the prescribing of antibiotics for respiratory tract infections (RTIs) by GPs based in the Netherlands. AIM: To assess, in patients with RTIs in Dutch general practice: the prescribing rates of antibiotics; the relationship between GP characteristics and antibiotic prescribing; and the type of antibiotics prescribed. DESIGN OF STUDY: Descriptive and prognostic. SETTING: Eighty-four GPs in the middle region of the Netherlands. METHOD: All patient consultations for RTIs were registered by 84 GPs during 3 weeks in autumn and winter 2001 and 2002. In addition, all GPs completed a questionnaire related to individual and practice characteristics. RESULTS: The mean proportion of consultations in which GPs prescribed antibiotics was 33% (95% CI = 29 to 35%) of all RTIs. This proportion varied from 21% for patients with upper RTIs or an exacerbation of asthma/COPD, to about 70% when patients had sinusitis-like complaints or pneumonia. Amoxycillin and doxycycline were the most frequently prescribed antibiotics, while 17% of the antibiotics prescribed were macrolides. Multiple linear regression analysis showed that the longer GPs had practised, the more frequently they prescribed antibiotics, especially in combination with relatively little knowledge about RTIs or the less time GPs felt they had available per patient. The final model, with seven factors, explained 29% of the variance of antibiotic prescribing. CONCLUSION: The prescribing behaviour of Dutch GPs might be improved with regard to choice of type and indication of antibiotics.