The oil and gas industry is very well known for taking care of the well-being of its employees. However, the nature of the working environment in the oil and gas industry in the Arabian Gulf, which is dominated by either harsh desert environment or by stressful office work, gives more chance for occupational health diseases to be present, perhaps more than other industries and working environments, leading to inevitable dangers. There were a number of studies that looked into the impact of working schedules on employees' health, but they focused on the offshore North Sea environment. To date, there is no comprehensive study that has been performed on such impact on onshore-based employees specifically in the Gulf region. This study utilised the information and studies available on the offshore working environment as a guideline. First, a statistical analysis was carried out on the records of 4700 employees of Petroleum Development Oman (PDO). The purpose of the analysis was to establish the main information on employees (gender, nationality and working schedule). Then, a survey was conducted and 172 responses were received. The purpose of the study was to gather and analyse data on employees related to occupational health cases. Information like gender, Body Mass Index, nationality, working schedule, job and qualification were collected. The survey also included sections on employees' occupational health diseases, satisfaction at work and preferred working schedule. Finally, the occupational health records, obtained from PDO's medical department, for the last few years were analysed and also the survey results were analysed and both sets of data were compared. The conclusion from this study is that the majority of the PDO employees suffer from several occupational health diseases. At the top of the list is stress at 42%. This represents a high frequency of stress cases. The other top four reported diseases in ranking order are back pain, headaches, Repetitive Strain Injury (RSI) and musculoskeletal diseases. The key recommendation from the study is that measures to provide a solution to 'arrest or reduce stress at work must be put in place in order for PDO to improve its work efficiency. This can be done by reviewing the work load and reducing bureaucracy at work. The flexible time introduced in PDO coastal location is not largely utilised and must be either changed or made more flexible. Ergonomics at PDO must be looked at continuously in order to reduce the number of back pain, Repetitive Strain Injuries and musculoskeletal cases. Finally, the study recommends that PDO should consider to stop using what was found to be a stressful schedule by other similar studies. This is the 62/29 schedule which requires employees from Asian countries to work continuously in the desert for 62 days 12-hours a day followed by 29 days of leave.