Objective: To assess the knowledge regarding hospital acquired infection (nosocomial infection) among health care workers of tertiary care hospital of Wah Cantt. Study Design: This was a Descriptive quantitative study design based on self-design questionnaire. Place and Study Duration: It was carried out from March 2018 to August 2018 involving health care workers working in tertiary care hospital of Wah Cantt. Materials and Methods: Data was collected through self-structured questionnaire from the health care workers working in tertiary care hospital of Wah Cantt. The collected data was analyzed through SPSS version 20, for proper analysis the data was presented in the form of percentage and frequencies for qualitative variables, mean and standard deviation was calculated for quantitative variables. Results: The results of the study showed that Health Care Workers had adequate knowledge regarding hospital acquired infection. The existing studies was done to explore the knowledge gap regarding hospital-acquired infection of Health Care Workers and how hospital acquired infection can prevent from one another in the hospital settings. Conclusion: The study gave a basic level of knowledge regarding hospital acquired infection (nosocomial infection) among health care workers. The health care associated infection (HCAIs) or the infections acquired from the hospital can be defined as the Infection, which occurs within the 48 hours of hospital admission or three days of discharge from hospital.