The existing models for machine requirements planning are based on the assumption of a constant production rate per machine throughout the planning horizon. This assumption is not valid in many production environments where the manufacturing productivity increases because of factors like: product and process redesign, more efficient maintenance and setup procedures, direct-labour learning, reduction of scrap losses, etc. The objective of this paper is to present the effects of improving manufacturing productivity on machine requirements planning, In addition, an integrated model which combines the aggregate production planning and machine requirements planning problems is discussed under the effects of manufacturing progress function.