The high energy radiotherapy linear accelerators (LINAC) offer considerable risk of radiation hazards to patient, worker and public if adequate safety measures are not taken into the account. Proper bunker designing with appropriate shielding is an important safety measure, which protects workers and member of general public. The present study describes the details of shielding of LINAC bunker in four radiotherapy centers of Karachi city. In order to conduct the study, shielding of five LINAC installed in four radiotherapy centers was assessed by considering real occupancy factor, dose limits for worker and public, etc. to verify that shielding of the bunkers conforms to the national and international standards like International Atomic Energy Agency and National Council on Radiation Protection and Measurement. After the assessment, it was concluded that all bunkers conform to the radiation protection requirements and present adequate shielded. This is an important step to achieve as low as reasonably achievable principle and protect workers and member of general public.