Received: July 2015, Accepted: November 2015Background: Ergonomics is a science that provides methods of creating reasonable adaption between occupation and worker by improving usability through consideration of job demands and human ability to satisfy them. A deep understanding of user's thoughts on and attitudes toward utilizing a tool could improve its design. In the present study, two cushions designed particularly for one of car industries , assembly line were tested considering usability. Materials and Methods: From among the 50 employees of the assembly line, 44 employees were selected randomly to participate in the study. The research tool consisted of a researcher-made questionnaire containing 29 questions in 5 subscales (usefulness, efficiency, effectiveness, satisfaction, and safety). The validity of the questionnaire was estimated by a specialist (CVI = 0.85) and its reliability was calculated using Cronbach's alpha (α = 0.87). Results:The mean scores of the 5 subscales of usefulness, efficiency, effectiveness, satisfaction, and safety were 6.5 ± 0.534, 6.5 ± 0.488, 5.3 ± 0.278, 6.4 ± 0.310, and 6.5 ± 0.534, respectively. Conclusions: Scores in all dimensions were above moderate and acceptable levels. Workers utilized them satisfactorily, and thus, producers can produce these cushions in large numbers without any problems. The performance of similar studies is recommended in designing other tools and instruments and the application of ergonomic principles in their design.