Previous studies have demonstrated that the use of recombinant human follicle stimulating hormone (rhFSH) for ovarian stimulation may be associated with a better outcome than human menopausal gonadotrophin (HMG), probably due to the absence of LH, higher FSH bioactivity and better quality of oocytes and embryos when rhFSH is used. Very few studies have examined the effects of different gonadotrophins on oocyte and embryo quality. In this prospective study, 40 women undergoing ovarian stimulation for intracytoplasmic sperm injection were randomized to receive a standard protocol of either HMG or rhFSH in down-regulated cycles. Prior to microinjection, each denuded oocyte was videotaped to assess nuclear maturity, morphology of zona pellucida, oocyte and polar body and the zona thickness, and diameters of oocyte and ooplasma. Fertilization and subsequent embryo development of each oocyte were followed. The embryologists were blind to the type of gonadotrophin each patient had received for stimulation. No significant differences were found between the two groups with regard to the demographic data, the ovarian responses and pregnancy/implantation rates. The percentage of metaphase II oocytes in the HMG and rhFSH groups were similar (86.9 versus 87.4% respectively). All other parameters assessing oocyte and embryo quality were also comparable between the two groups.