Background: New methods are needed to optimize intracytoplasmic sperm injection (ICSI) outcomes in oligoasthenozoospermic (OAS) men. We evaluated the level of DNA fragment index (DFI) in OAS men and its impact on ICSI outcomes. In addition, we used the zeta potential method for sperm selection to investigate the efficacy of this technique in improving ICSI outcomes. Materials and Methods: This cross-sectional study was performed on 95 couples. Sperm parameters and sperm DNA fragmentation (SDF) were measured. The couples were divided into the following 3 groups: group I (n=30) where SDF was between 15% and 30%, and routine sperm was selected on the basis of motility and morphology; group II (n=34) where SDF was more than 30%, and the routine sperm selection method was applied on the basis of motility and morphology; and group III (n=31) where SDF was more than 30%, and the sperm selection was performed on the basis of the zeta method. The fertilization rate, embryo development, embryo quality, and implantation rate were evaluated in these 3 groups. Results: The fertilization rate was significantly higher in group I compared with group II (P<0.05). The embryo development rate in group I was significantly higher than that in group II (P<0.001) and group III (P<0.05), and it was significantly lower in group II compared with group III (P<0.05). The embryo quality was higher in group III compared with group II (P<0.01). The implantation rate in group I was significantly higher than that in group II (P<0.05) and group III (P<0.05). Conclusion: The present study indicated that a higher level of SDF has an adverse effect on the ICSI outcome. Furthermore, the zeta potential technique can be a useful method for sperm selection in OAS men. [GMJ.2018;7:e1107]