Background: Blood Stream Infections continue to be a leading cause of mortality and morbidity especially in ICU settings. Infections leading to sepsis are usually bacterial, but may be fungal or viral. Aim: The aim of the present study was to identify bacterial etiology in patients with clinically diagnosed blood stream infections. Material and methods: The study was a prospective, observational study which was carried in the Department of Microbiology, MGM Medical College and LSK Hospital, Kishanganj, Bihar, India. A total of 300 patients with clinically diagnosed sepsis were chosen for the study. Suitable specimens from all these patients were subjected to Gram staining and culture on suitable culture media, and isolates were identified by colony characters and the battery of standard biochemical tests. Results: Out of a total of 300 samples, 91 showed positive culture for bacterial isolates; 52 isolates were Gram negative (57.1%) and 39 were Gram positive (42.9%) bacteria. Out of the Gram positive isolates Staphylococcus aureus was the commonest and Klebsiella spp was the most frequent isolate among the Gram negative organisms. Conclusion: As blood stream infections remain a formidable challenge in clinical settings, it is imperative to know the etiology of an intercurrent infection so that appropriate therapeutic measures can be taken at the earliest.