Abstract Background and objective: The intensive care unit (ICU) often called as the epicentre of infections, due to its vulnerable population. It has been reported that the incidence of nosocomial infections in the intensive care unit (ICU) is about 2 to 5 times higher than in the general inpatient hospital population. The present study aims to know the causative organisms and antibiotic susceptibility of infections in intensive care units. Methods: It is a prospective study with 300 patients with suspected infections included were included. Samples were processed as per standard guidelines and the colonies were identified according to standard biochemical tests. Antibiotic susceptibility testing was done on DMC Darbhanga, disc diffusion test. ESBL production was tested by disc diffusion method as in CLSI phenotypic method. Conclusion: There is increase in number of infections in ICUs due to multidrug resistance organism ,which is the big public health threat and challenge for both prevention and treatment of infections. Thus the incidence rates, the causative agents and their susceptibility play a vital role in the management of infections in ICU.