In performance evaluation literature, although the combination of some variables such as age, gender, experience, observation time, and interpersonal affect has been widely considered in determining employee performance, no investigation has indicated the influence of workplace conditions on job performance. This study reports the effects of job characteristics (physical efforts and job grade), ... [Show full abstract] and working conditions (environmental conditions and hazards) in addition to experience and education level on task performance and contextual performance. A total of 154 employees in 18 teams at a medium-sized metal company participated in this study. Seven criteria for task performance and 16 for contextual performance were used for measuring employee performance. The results showed that there were substantial relationships between employee performance both job grade and environmental conditions. Poor workplace conditions (physical efforts, environmental conditions, and hazards) result in decreasing employee performance consisted of following organization rules, quality, cooperating with coworkers to solve task problems, concentrating the tasks, creativity, and absenteeism.Relevance to industryUnpleasant working conditions in workshops have different effects on each of the job performance indicators. This study highlighted that training program designed to enhance job performance of the employees working under poor workplace conditions should focus on organizational rules in terms of occupational health and safety.