Human Errors were attributed as one of the main causes of many industrial incidents and accidents in workplace particularly in petrochemical, oil and gas plant’s operation. One of the main contributors to human errors is fatigue, and fatigue occurred either due to insufficient sleep or disruptions in the normal sleep cycle. Ultimately, the shift workers have high tendency to experiences fatigue due to shift rotation. Petrochemical, oil and gas plant adopted shift work schedule to ensure the continuity and to optimize the utilization of workforce. It is critical to analyse the relationship between fatigue and human errors to prevent accident/incident at the workplace. A combination of quantitative and qualitative research was conducted using questionnaires for collecting primary data and a survey of literature related to fatigue and human errors for collecting the secondary data. The study was carried out to investigate the possible types of human errors and their causes that lead to incident/accident in petrochemical, oil and gas plant’s operation and to evaluate the relationship between fatigue and human errors. The sample was taken from shift worker of operation team that consists of field operators, DCS operators and shift controllers. The study results demonstrated that there is a clear link between fatigue and human errors, human errors prevention done by preventing the fatigue. There are four types of human errors were investigated (lapses, slips, mistakes, and procedure violation). Fatigue can be prevented by modifying the working hours, reducing working hours, improving the working environments (lighting, display, noise, colour similarity, appearance similarity), simplifying the tasks, the proper ratio between manpower and workload. The responsibility to manage fatigue should be taken by both employers and employees.