Background: Ergonomics is the scientific study of human work. The objective of ergonomics is to obtain an effective match between the user and work station to improve working efficiency, health, safety, comfort and easiness to use. Neglect of ergonomic principles brings inefficiency and pain in the workplace. Objectives: The purpose of this study is to establish the content validity of an instrument (Questionnaire) to assess Ergonomic Knowledge of Computer professionals using a rigorous Judgmentquantification__ampersandsignnbsp;process. Methods and Measures: The Draft Questionnaire composed of 35 items related to Knowledge about Musculoskeletal disorders and its risk factors, Working Postures, Seating, Keyboard/Mouse, Monitor, Table and Accessories and finally Rest breaks and Exercises. A panel of 9 experts validated the Draft Ergonomic Knowledge Questionnaire. After all correspondence was received regarding Content validity for each item, The Content Validity Index (CVI) is calculated by tallying the results of the experts based on the degree to which the experts agree on the relevance and clarity of the items. Finally, a Focus group was held to evaluate the instrument for overall comprehensiveness. Results: Results from the panel of experts yielded a 0.98 overall Content validity index. Few experts suggested minor revisions regarding the clarity or wording of the items, and those revisions were incorporated into the instrument. Conclusion: The process used to determine Content validity proved to offer consistency and structure to the instrument development. High CVI scores were generated for the items judged relevant to the content domain as well as for the overall instrument. The results support the Content validity of this Questionnaire as a tool to assess the Ergonomic Knowledge of Computer Professionals.