Received September 14, 2009
Accepted December 12, 2009

Objective: To develop a comparative study among intracytoplasmic morphologically selected sperm injection (IMSI) and conventional intracytoplasmic sperm injection (ICSI), assessing the efficacy of both in fertilization rates, cleavage and embryo quality. Methods: 36 cycles of intracytoplasmic sperm injection have been analyzed. In these cycles were obtained 603 mature oocytes (MII), which were injected with sperm selected by two different techniques. The oocytes obtained of each patient were divided into two groups (A and B). In group A (302 oocytes), were employed, to assess the morphology of sperm to be injected, the conventional equipment that provides optic magnification of 400 X (conventional ICSI). In group B (301 oocytes), were employed an equipment that provides an optic magnification of 6800X, (IMSI). After embryo culture was performed, fertilization rates, cleavage and embryo quality until day 3, on each group, were analyzed. Results: The total fertilization rate in group A was 78,81%, and in group B, 81,06%. The cleavage rate in group A was 97,29%, and in group B, 96,41%. The percentage of good quality embryos (grade I e II), in day 2, in group A was 79,53% and in group B, 78,13%. The percentage of good quality embryos on day 3, in group A was 77,41% and in group B 78,81%. Conclusion: There were no significant difference in fertilization rates, cleavage and embryo quality to day