We aimed to describe the incidence of new episodes of molluscum contagiosum, scabies and lichen planus presenting to general practitioners in England and Wales. We examined data collected in a sentinel practice network (the Weekly Returns Service of the Royal College of General Practitioners) in which about half a million persons were observed each year over the period 1994–2003. The incidence of molluscum contagiosum in males was 243/100000 person-years and in females 231; of scabies, males 351, females 437; of lichen planus, males 32, females 37. Incidence varied by year and age. Ninety per cent of molluscum contagiosum episodes were reported in children aged 0–14 years, where incidence in 2000 (midpoint of a 6-year period of stable incidence) was 1265/100000 (95% CI 1240–1290). Scabies affected all ages and annual incidence ranged between 233 (95% CI 220–246) in 2003 and 470 (95% CI 452–488) in 2000. Lichen planus occurred chiefly in persons aged over 45 years: incidence (all ages) ranged between 27 (95% CI 23–31) in 2003 and 43 (95% CI 37–49) in 1998. The relative risk of female to male incidence (all ages) of molluscum contagiosum was 0·95 (95% CI 0·91–0·99); of scabies 1·25 (95% CI 1·21–1·28); and of lichen planus 1·19 (95% CI 1·08–1·13).