The main objective of this paper is to design a dentists’ workspace for optimal performance using JACK, developed by Siemens Corporation (Siemens PLM Software Inc.,) is a Digital Human Modeling (DHM) software package capable of simulating human involved in any number of tasks and performing ergonomic analysis. Dentists all over the world are suffering from Musculoskeletal Disorders (MSDs) that are resulted by improper work postures, repetitive tasks, and forced positions for longer time. Thus, to reduce the effects of MSDs among dentists, ergonomic assessments have been implemented to evaluate their work postures and determine the risks at their workspaces. JACK provides some design tools such as Rapid Upper Limb Assessment (RULA) and Ovako Working Analysis System (OWAS) for performing ergonomic analysis of virtual products and work environments. OWAS and RULA are the ergonomic assessments that are used to examine the work postures and the MSDs for dentists resulted by the improper postures by simulating their postures on JACK. By using the results of OWAS and RULA, workspaces of the dentists are redesigned and their postural angles and positions are modified. The final analysis of OWAS and RULA showed that improvements were significant to reduce MSDs while the dentists perform their tasks.