Introduction: Bloodstream infection is the most common health care associated infection and a significant cause of mortality and morbidity. Early and appropriate antibiotic therapy is crucial in the treatment of BSI. In the current era of improper use of antibiotics, there is a rise of antimicrobial resistance in bloodstream infections. Policies should be devised to control this by the proper and effective use of antibiotics. Aim and Objectives: To study the etiological microbial agents of bloodstream infections and their susceptibility pattern in a tertiary care centre over a period of one year. Materials and Methods: 467 blood culture samples received from different departments of GGH, Vijayawada, A.P, from October 2016 to September 2017, were processed as per standard microbiological procedures. Antimicrobial susceptibility testing was done as per CLSI guidelines. Results: Out of 467 blood culture samples, 104(22.2%) were culture positive, 363 were culture negative. Among culture positives,43( 41.3% )were Staphylococcus aureus, 17(16.67% )Klebsiella species, 4 Escherichia coli. On repeated subcultures 35( 34.3%) Coagulase negative Staphylococcus, 3(2.9%)Pseudomonas species were isolated. Gram-positive isolates were mostly sensitive to Vancomycin, Amoxycillin plus Sulbactam and resistant to ampicillin and cefotaxime. Gram negative isolates were mainly sensitive to Piperacillin Tazobactam, Imipenem and resistant to Levofloxacin, Cefotaxime. Conclusion: The present study shows that Staphylococcus aureus and Klebsiella species are the most common causative agents and most effective antibiotics are vancomycin and Piperacillin tazobactam, Imipenem, respectively.