['To conduct a prospective randomized study in order to investigate the effect of recombinant HCG (rHCG) on oocyte nuclear and cytoplasm maturity compared to urinary HCG (uHCG), for inducing ovulation in women treated with ICSI for male factor infertility.', 'We compared 89 patients randomly assigned to one of the two study groups. Group A consisted of 42 women who received a subcutaneous (s.c.) injection of 250 microg rHCG and group B consisted of 47 patients receiving an intramuscular (i.m.) injection of 10,000 IU uHCG.', 'Patients treated with rHCG showed a rate of metaphase II oocytes, a number of metaphase II oocytes with mature cytoplasm and a rate of metaphase II oocytes with mature cytoplasm calculated from total MII oocytes statistically higher than in patients treated with uHCG. However this differences were not associated with a significantly better clinical outcome.'] Does recombinant HCG for triggering ovulation increase the rate of mature oocytes in women treated for ICSI?