IT professionals’ job satisfaction is important in minimizing turnover, improving job performance, minimizing absenteeism, and increasing the level of job involvement. The primary purpose of this study is to measure the job satisfaction of IT professionals and to identify which factors influence job satisfaction the most in Hanoi’s IT companies. The study also investigates the relationship between job satisfaction factors and the overall job satisfaction by using the Job Descriptive Index (JDI) and Job General Index (JGI) questionnaire to evaluate the construct validity of factors. Data were gathered from a survey of 326 IT professionals in systems development to capture perceptions regarding workrelated factors on job satisfaction and organizational commitment. The results of this study indicate that compensation and benefits, co-worker, promotion opportunities, nature of work, and supervision are positively related to job satisfaction. Based on these findings, the study provides implications to business executives in the IT businesses.