OBJECTIVE To test the hypothesis that the free L-camitine helps in maintaining normal fertility. METHODS The present descriptive study was designed to show comparison of seminal free L-carnitine and sperm quality. Case controlled convenient sampling was used to assess infertile male subjects from fertile. A total of 61 adult males were selected by consent, and were categorized as fertile and infertile on the basis of history and semen analysis. Subjects were selected from Infertility Clinic, Reproductive Health Services Centre of Jinnah Postgraduate Medical Centre, Karachi. Subject's with history of pelvic surgery, or suffering from diabetes mellitus, thyroid diseases or using steroids, antihypertensives and antipsychotics drugs were excluded from the study. Groups were compared using student's t-test and p < 0.05 was considered as statistically significant. RESULTS The mean values of sperm count, total motility and normal morphology of asthenospermic and oligoasthenoteratospermic were found significantly (p < 0.05) lower when compared with fertile (control). When levels of seminal free L-carnitine were compared among groups, the result showed that infertile subjects had significantly lower (P < 0.001) when compared to fertile subjects with lowest concentration in azoospermic group. CONCLUSIONS The results of this study suggested that L-carnitine level in seminal plasma plays an essentialrole in maintaining male fertility. However larger studies on Pakistani population with this approach are warranted.