Preimplantation genetic diagnosis (PGD) of aneuploidy was performed on 49 patients diagnosed with severe male factor infertility and a poor prognosis of pregnancy due to: 1) advanced maternal age; 2) repeated IVF failures; and 3) altered karyotype in peripheral blood. The results attained were compared to those derived from 28 normospermic patients presenting the same poor prognostic indications. In all, 445 embryos were selected for fluorescent in-situ hybridization (FISH) analysis on the basis of their morphological evaluation. In 23 embryos (5%) no result was obtained, whereas 168 embryos (40%) were diagnosed as normal and 206 (49%) as FISH abnormal. Following PGD, 60 patients had at least one chromosomally normal embryo transferred resulting in 15 clinical pregnancies. The analysis of the embryos derived from intracytoplasmic sperm microinjection (ICSI) in comparison to those obtained after conventional insemination, revealed that the percentages of FISH abnormal embryos were similar between the two groups (48% versus 50%). Similarly, the distribution of chromosomal abnormalities did not vary significantly; however, a higher incidence of anuclear blastomeres resulted following ICSI (14% versus 6% after conventional insemination). These data suggest that no increase in terms of chromosomally abnormal embryos is associated with the condition of severe male infertility. However, genetic counselling in ICSI patients is recommended in order to evaluate the possibility of an increased genetic risk and its transmission to the next generation.