The impact of rotational work system on the mood and energy level among Oil and Gas workers was evaluated. The design was set in Port Harcourt metropolis Nigeria and questionnaire, cohort session and interviews were the instruments deployed. Questionnaires were administered to randomly selected workers from international Oil and Gas Companies located in Port Harcourt, Questions that bothered on the effect of rotational work on the mood and energy level of Oil and Gas workers were posed. It was observed that 38.8% and 41.2% agree and strongly agree that their mood is affected on site while 13.8% remained neutral. Interestingly, over 80% of Oil and Gas workers agreed to feeling of anxiety from the interview and cohort sessions. 40% and 43.8% of workers agree and strongly agree respectively that rotational work does affect their energy on site. Obtained median of 4 means that over 50% of the response belongs to the category that agree strongly agree while a mode of 5 has more responses in the category of strongly agree which is in agreement with results from the percentage frequency. Rotational workers were affected by absence from family and loved ones, social isolation and constant reminder of hazard and working in hazardous environment with work pressures and unrealistic deadlines. These cause depression and general dissatisfaction with life. Results from interviews revealed neglect of mental wellness of workers. The Oil and Gas workers are willing to face these hazards because of the economic gains arising from their work, however provision of recreational amenities and making policies that bring the Oil and Gas workers back home every seven days forbidding the schedule of trainings and workshops during time off duty will make rotational work more bearable.