We evaluated the role of dopamine (DA) transporter gene polymorphism in lifelong premature ejaculation (LPE) and its role in determining the response to paroxetine and escitalopram. Eighty consecutive patients and controls were recruited. Sixty of them suffered from LPE. They were divided into two equal groups. One group received paroxetine 20 mg daily for 3 months and the other one received ecistalopram 20 mg daily for 3 months. Their wives were instructed to measure the intra-vaginal ejaculation latency time using stopwatch. Five milliliters of blood was withdrawn from patients and controls for PCR analysis. The present study revealed that the mean ages of the patients and controls were 41.42 and 36.4 years, respectively. The majority of the patients were of (10R/10R) genotypes of the DA transporter gene polymorphism, whereas the controls were of (6R/6R) genotypes and this revealed statistically significant result (P-value = 0.001). Both paroxitine and escitalopram significantly delayed ejaculation in the responders (P-values = 0.001 and 0.001, respectively). The study revealed significant association between such response and DA transporter gene polymorphism (P-values of fold increase and log FI were 0.019 and 0.010, respectively). To the best of our knowledge, this is the first report to demonstrate a highly significant association between such response and DA transporter gene polymorphism in patients with LPE.