In sexual crime cases, it is difficult to obtain a male short tandem repeat (STR) profile from samples with high concentration of female DNA. In the cases, it is important to obtain Y chromosome STR(Y-STR) profile from the samples in order to solve the cases. Occasionally, intact Y-STR profile is found in samples containing the male DNA less than the minimum detection limit in sexual crime cases. At this point, we wonder whether the quantitative value of male DNA was affected by the high concentration of female DNA. Using two Y-STR kits, Y-STR profiles were examined in the mixed DNA samples of female DNA isolated from vaginal fluid and male standard DNA. It was confirmed that high concentrations of female DNA did not affect the acquisition of Y-STR profile in the mixed DNA samples. However, the female DNA affected the quantitative values of male DNA in the samples. This study is expected to contribute to the reliability of obtaining intact Y-STR profile in mixed DNA samples with concentrations below the minimum detection limit for obtaining the Y-STR profile.