Objective: To assess the effect of the laser prostatectomy (LP) procedure on the serum prostate-specific antigen (PSA) levels. Patient and Methods: The serum PSA level was determined in 41 patients with benign prostatic hyperplasia 1 day before and 1, 3, 7, 15, 30, and 90 days after LP. All patients underwent preoperative evaluation with routine blood tests, serum PSA level, IPSS symptom questionnaire, intravenous pyelography, uroflowmetry, post-void residual urine measurements, and transrectal ultrasonography (TRUS). IPSS symptom questionnaire, uroflowmetry, post-void residual urine measurements, and TRUS were repeated 3 months after LP. Results: PSA levels showed a statistically significant increase 24 h after LP, then a slow decrease and by 1 month the PSA levels had returned to their initial levels. A statistically significant positive correlation was found between the PSA level 24 h after LP and the amount of energy applied to the prostate during operation (r 0.87, p < 0.0001). After 30 and 90 days the mean PSA values were under the pre-prostatectomy concentration. The mean PSA values at 30 and 90 days were statistically significantly lower than those measured before treatment (p < 0.05). There was a statistically significant positive correlation between the reduction in PSA and the reduction in prostate weight 3 months after LP. Conclusion: This study showed that LP produced a variable rise in PSA, with a peak rise in PSA occurring 24 h after the procedure. In some patients, the serum PSA returned to baseline by 15 days. But, after 15 days the mean PSA level was still greater than the preprocedure value. Therefore, we recommend that blood should not be sampled for PSA for at least 30 days after LP. The mean PSA levels 30 and 90 days after treatment were lower compared with the preoperative levels. This low level of PSA can probably indicate a reduction in prostate volume following LP.