Background Cognitive impairment is a common complication of Severe Traumatic Brain Injury (STBI). One of cognitive problems following STBI is impaired executive functions which involve high-level cognitive processes and their dysfunction can lead to reduced quality of life. Objective This study aims to investigate the cognitive impairment in men with STBI compared to healthy men. Materials and Methods This causal-comparative study was conducted from February 2017 to July 2019 on 20 male patients aged 30-55 years with a history of STBI in the past one year admitted to the intensive care units of Shohaday-e-Haftom-e-Tir and Baqiyatallah hospitals in Tehran, Iran and 64 healthy men who had met all inclusion criteria. Both groups were measured by the Wisconsin Cards Sorting Test (WCST). Results There were significant differences between the two groups in WCST parameters including the number of categories completed, perseverative errors, correct and wrong responses, response time, number of trials to successfully complete first category, and conceptual level responses (P<0. 01). Patients with STBI had a lower overall WCST score than the healthy subjects. Conclusion It is necessary to pay special attention to cognitive impairment in STBI patients in their clinical and legal evaluations and psychological interventions.