OBJECTIVE To compare the pregnancy rates achieved by intrauterine insemination or timed intercourse in gonadotrophin stimulated cycles in couples whose only detectable abnormality was poor sperm quality. METHODS Sixty-two couples with primary or secondary infertility due to male factor entered the study. The 62 couples were randomly equally divided into two groups. Each group began one of the two treatment modalities (controlled ovarian hyperstimulation in conjunction with timed intercourse or intrauterine insemination) for three consecutive cycles and then switched to the alternative treatment after one rest cycle, if pregnancy was not achieved. RESULTS Five pregnancies (3.9%) were achieved after 128 cycles with timed intercourse and 15 pregnancies (11.5%) after 130 cycles with intrauterine insemination. The difference was found to be statistically significant (P < 0.05). CONCLUSIONS We suggest that intrauterine insemination during hMG stimulated cycles improves the pregnancy rates of couples whose only detectable abnormality is poor sperm quality.