Objective: Studies on online social networking and its impact on life satisfaction of young adults are scant in Sri Lanka. This study aspired to fill this gap by exploring selected aspects of life satisfaction and online social networking. Methods: A cross sectional study was carried out at a Faculty of Medicine of a Sri Lankan University. A total of 459 medical students from first to fourth years of study participated. Four self-administered scales on (i) Use of Internet Social Networking; (ii) Meeting Friends; (iii) Social Support; and (iv) Life Satisfaction were adapted from existing literature and used. Results: A majority of medical students uses Facebook while a less number uses online chat rooms. Even with greater online social networking, there were more actual meetings with friends; these meetings were positively associated with perceived social support from friends; and these meetings had an impact on students’ perceived life satisfaction. Conclusions: The study indicated that online social networking has beneficial effects on medical students, in particular in the area of perceived life satisfaction. However, these benefits should be weighed alongside the detriment to privacy and medical professionalism.