High level of procalcitonin can be used to diagnose gram negative bacteremia. In elderly, there is a decline in the immune system that can affect the body’s response to infection. This study was conducted to investigate difference of procalcitonin levels between elderly and non-elderly patients. Retrospective study was conducted at Dr. Cipto Mangunkusumo General Hospital (RSCM) from December 2013 to January 2018. Patients with gram negative bacteremia age of >18 years were included in this study. Patients were categorized into two groups: non-elderly (<60 years) and elderly patients (≥60 years). Chi-Square test is used to analyze categorical variables, Mann Whitney test is used to analyze nonparametric variables. The study enrolled 247 gram negative bacteremia patients, consisting of 142 (57.5%) women and 105 (42.5%) men. There were no significant differences in sex, complete blood count, liver function test and microorganisms in both groups. The three most common of microorganisms were Klebsiella pneumoniae, Acinetobacter baumannii and Escherichia coli. Bacteremia Salmonella species were found only in non-elderly group. Concentrations of ureum (p=0.027), creatinine (p=0.049) were significantly higher in the elderly group than in the non-elderly group. Procalcitonin concentrations were significantly higher in the non-elderly group compared with the elderly group (p=0.005). Elderly patients with gram negative bacteremia have decline in kidney function and lower procalcitonin levels compared with non-elderly patients.