Occupational noise exposure is a serious physical risk factor leading to occupational diseases including hearing loss. In this study, occupational noise measurements taken at seven natural stone processing plants operating in Sivas, Turkey and its environs are evaluated in accordance with the task-based assessment method given in TS EN ISO 9612-2009 standard. Though the processes in natural stone processing plants are similar, significant differences were observed in the noise levels, which are often above the limits specified in the relevant regulation. The highest noise levels to which workers were exposed are S/T, bridge cutting, sizing/honing, head/side cutting machines while the lowest noise levels were from narrow polishing machine and gang saw machines. In plants B, F and G the S/T block cutting machines, in plants B and D the head/side cutting machines, in plants C and E the sizing/honing machines and in plant D the bridged cutting and narrow polishing machines exposed workers to noise levels above the lowest exposure action value of 80 dBA. The bridge cutting machine in plant D exposed the workers to noise levels above the highest exposure action value of 85 dBA. High noise emitting machines were proposed to be isolated in separate compartments.