Incidence rates of six respiratory infections were calculated from sentinel practice data of 33,407 reports coming from 31 general practitioners in Queensland over 34 months in 1986/1988. Upper respiratory tract infection had an annual incidence of 301 per 1000 people, most in children aged under five, and a winter rate twice the summer rate. Sore throat (incidence 112:1000) and Infectious mononucleosis (incidence 2.7:1000) had little seasonal variation and were maximal among those aged 15-19 (in whom there was one case of Infectious mononucleosis for every 14 sore throats). Influenza (incidence 44:1000) underwent a prominent epidemic in the winter of 1988. Measles (incidence 1.9:1000), and pertussis and pertussis-like syndrome (incidence 0.8:1000) were most commonly reported in the under-fives, and rarely among adults. Sentinel practices networks collect useful epidemiological data from which disease incidences can be calculated.