Employee's workload of PT XYZ is predefined as relatively high if it takes into consideration manpower and the task amount. The exceeded workload can affect the job satisfaction of the employee. Hence, it is needed to do an assessment to measure the workload and its effect on job satisfaction. The workload was measured by NASA-TLX, which consists of mental demand, physical demand, temporal demand, performance, effort, and frustration. At the same time, job satisfaction is measured by a questionnaire that consists of remuneration, promotion, superior's assistance, and colleagues' assistance. The objects of this study are an employee of the Sustainability and Operation Department. The research result in workload is definitely high. Besides that, there is a correlation between workload and job satisfaction. There are two correlation models, positive and negative. A high workload can improve job satisfaction, but otherwise, it can decrease job satisfaction.