In a two-month study in an urban general practice of eight partners, 11.7 per cent of patients failed to attend for their appointments. Defaulters were younger than a control group of attenders, but the male to female ratio was almost identical. Annual consultation rates for defaulters were slightly lower than controls. Return visits had a default rate of 18 per cent and there was a strong statistical correlation between how and when an appointment was made and the default rate, with a maximum default rate of 19 per cent if the appointment was made between one to two weeks in advance. There was a significant difference in default rate between the partners (range 7.2-14.6 per cent) and the default rate was lowest on Mondays (9.7 per cent) and highest on Fridays (14.9 per cent). The majority of the defaulters had only defaulted once in the previous 12 months. These findings have important implications when planning an appointment system and asking patients to return for follow-up.