Invasion of the blood stream by microorganisms constitutes one of the most serious situations in infectious disease. Aim: The aim of this study was to identify the bacteria that caused blood stream infections. Methods: This six months prospective and observational study was performed in the department of microbiology at All India institute of Medical Science (AIIMS), New Delhi, India, on 280 blood samples of patients admitted in wards and various ICUs. Microbial detection and identification were done by fully automated BacT/Alert 3D and VITEK 2 systems, respectively. Results: Of the 280 suspected cases, blood culture was positive in 186 (66.4%) cases. Of the 186 isolates, 123 (66.12%) were Gram negative bacterial isolates of which the predominant were Klebsiella pneumoniae (27.64%), Pseudomonas aeruginosa (16.26%), and Escherchia coli (15.44%). Of the positive isolates, 63 (33.87%) were Gram positive bacteria of which MRSA (36.50%) was the predominant organism followed by MSSA (31.74%) and MRCoNS (17.46%). Conclusion: In this study, blood culture was positive in a relatively high proportion of suspected cases of blood stream infections. Automation has higher sensitivity and specificity than conventional methods and can help in significantly reducing mortality and morbidity of blood stream infections.