Despite the direct placement of sperm within the oocyte, fertilization failure still occurs after ICSI. This study was accomplished to analyze the chromosomes in oocytes failed to fertilize after ICSI comparing to oocytes failed to fertilize by conventional in vitro insemination. Seventy-four ICSI cycles and 122 conventional IVF cycles were included in analysis. Included unfertilized oocytes were from 74 patients (mean age = $32.7{pm}3.7$). Ninety-three oocytes were informative and 83 oocytes were legible for cytogenetic analysis. Sixty-two oocytes out of 83 (74.7%) had normal chroruosomes, while 15 (18.1%) were hypoploidy, 6 (7.2%) were hyperploidy. Eighteen oocytes out of 93 (17.6%) were premature chromosome condensation (PCC). Two hundred ninety-four unfertilized oocytes after conventional insemination were subjected to chromosomal analysis and 180 oocytes were legible for analysis. One hundred thirty-two oocytes out of 180 (73.3%) were normal, while 22 (12.2%) were hypoploidy, 20 (11.1%) were hyperploidy, and 6 (3.3%) were polyploidy. Twenty-two oocytes (12.2%) were PCC. There was no difference in chromosomes between oocytes that failed to fertilize after ICSI or conventional insemination. High PCC rates in fertilization-failed oocytes suggest that oocytes maturity is another important factor in achieving successful fertilization.