A retrospective analysis in 50 couples of 53 cycles of intracytoplasmic sperm injection (ICSI) with immotile spermatozoa from testicular-retrieved spermatozoa was performed to evaluate whether total immotile spermatozoa achieved after testicular sperm extraction could fertilize ova and result in pregnancies. We assessed the efficacy of ICSI with totally immotile testicular spermatozoa extracted from the testes of azoospermic patients with severe spermatogenic failure (group 1) and compared these results with those from spermatozoa which were recovered after several hours of incubation and were motile (group 2) at the time of injection. In 19 cycles, only totally immotile spermatozoa were injected at the time of ICSI. For the remaining 34 cycles, at least one motile spermatozoon was found for injection. The oocyte fertilization rates were 51% for group 1 and 62% for group 2 (P < 0.02). Eighteen of 19 cycles in group 1 (90%) and all 34 (100%) cycles in group 2 had embryos for replacement. The mean number of embryos per cycle was 5.2 +/- 0.8 and 7.5 +/- 0.9 in groups 1 and 2 respectively; this and the embryo quality (cumulative embryo scoring = 40 +/- 8 for group 1 and 50 +/- 7 for group 2), and clinical pregnancy rates (15.8% per oocyte retrieval in group 1 and 23.5% in group 2) were not significantly different between groups. Fertilization, cleavage and pregnancy can be achieved with intracytoplasmic testicular sperm injection from patients with immotile spermatozoa, at levels comparable with those of ICSI using motile spermatozoa.