Mechanization of work processes in agro-based industries through the employment of improved tools and/or equipment powered by either fuel or diesel engines reduce tedium and drudgery on the work-ers as well as improve the overall productivity and production. However, it also leads to health threat to the workers through environmental noise pollution. This study assessed the occupational noise expo-sure of workers in three different palm oil mills. The noise level was measured using a noise metering device (model 1352) and noise descriptors (L10, L50, L90, Lav, LAeq, Total Sound Pressure Level (Tspl), DOSE (%) and TWA). The occupational health effects of noise exposure were deduced us-ing a semi-structured questionnaire. The noise exposure was assessed during the palm nut digestion, and nut and pulp separation job operations as the noise emanates from the diesel powered engine, palm nut digester and nut and pulp separator. The average noise levels obtained from the palm oil mills during palm nut digestion, 99.36 (SD = 4.16) dBA and pulp separation, 98.18 (SD = 3.07) dBA, exceeded the recommended 85 dBA for an 8-hour exposure period permissible noise exposure limit standard by the NIOSH. The independent t-tests for noise level between off-working and working periods disclosed p < 0.05 – significant noise exposure. The self-reported effect of the noise exposure level on the workers was interference with communication - 100%, tinnitus - 70%, ringing sensation - 76.75%, and noise stress - 73.30% of the workers. This research will inform the operators of the need for appropriate personal protective equipment usage and equip Government regulatory agencies to make appropriate regulations in order to protect oil mill workers.