One hundred and five couples with unexplained infertility and 43 couples whose infertility was thought to be due to reduced sperm motility were recruited. The median duration of infertility was 36 months (range 12-168). Couples were randomly allocated to either using Clearplan home ovulation detection kits for 3 cycles or were advised about the optimal time during their menstrual cycle to achieve a pregnancy. The clinical details of the 2 groups were similar. In couples with unexplained infertility over the study period 10 (20.4%) in the Clearplan group and 9 (16%) in the control group conceived with 58% of pregnancies occurring in the first cycle. In couples with reduced sperm motility, the results were disappointing with only 2 (8%) pregnancies in the Clearplan group and 2 (11.1%) in the controls. Assisted reproduction technology may not be justified as the first line of management in patients with unexplained infertility.