Background: Varicocele is the most common cause of male infertility. 20-30% of men with varicocele are infertile .The clinically obvious varicocele is identifiable and correctable cause of male infertility, but less is known about the subclinical varicocele and its relationship to infertility .However, subclinical varicocele seems to be an important causal factor in infertility and hence scrotal ultrasonography has lead to its increased use in diagnosis of subclinical varicocele. The present study is undertaken to reveal incidence of subclinical varicocele in patients with severely impaired fertility potential. Aim: To find out prevalence of subclinical varicocele in subjects of severely impaired fertility potential. Material and methods: The semen samples were obtained from 31 male partner (age- 25-40 years) of infertile couples (sperm count less than 1million/ml) attending the infertility clinic of Physiology Department, MGIMS, Sevagram. They were analyzed for routine seminogram parameters. In this study we evaluated male subjects with severely impaired fertility potential by scrotal ultrasonography, Follicle Stimulating Hormone, Luteinizing hormone & free testosterone. Results: The subclinical varicocele was present in 12 subjects out of 31 infertile males evaluated. Percentage prevalence of subclinical varicocele was observed to be 39%. Hormonal levels of all the subjects studied were within normal limit. There was no significant difference in testicular volume of affected side & contra lateral side of infertile male subjects. Conclusion: Scrotal ultrasonography is an important investigation to reveal subclinical varicocele for early diagnosis and management of these infertile male subjects.