The aim of the study is to investigate whether there is an effect of adult circumcision on ejaculation parameters and to research the relationship between intravaginal ejaculation latency time (IELT) and premature ejaculation diagnostic tool (PEDT). Adults who underwent voluntary circumcision between September 2010 and November 2011 were enrolled in this prospective study. The IELT before and 3 months following circumcision was recorded. Also, PEDT was filled out before and 3 months after circumcision. During statistical evaluation, the comparison of situations before and after circumcision was made using IELT averages and PEDT total scores. Furthermore, the correlation between changes in IELT and PEDT has also been evaluated. A total of 30 volunteers (mean age 21.25 ± 0.44) were enrolled in the study. The volunteers’ mean and median IELT before were 104.36 ± 66.21 and 88 (26-307) seconds, whereas mean and median IELT after circumcision were 123.56 ± 54.44 and 107.5 (67-300) seconds, respectively. The increase after circumcision was statistically significant (P = 0.001). The mean and median PEDT score were 4.26 ± 2.91 and 3 (1-12) before, and 2.63 ± 1.82 and 2 (0-7) after circumcision. Improvement was statistically significant (P<0.0001). No correlation could be found between ejaculation time and PEDT scores. Circumcision during adulthood does not adversely affect ejaculatory function; it may slightly improve. However, it could not be interpreted as a justification for circumcision in men with premature ejaculation (PE).