Cotton pickers with on-board module builders (OBMB) eliminates the need for boll buggies, module builders, the tractors, and labor needed to operate this machinery. Additionally, field efficiency may be increased due to less stoppage for unloading and/or waiting to unload. This study estimates the cost of production per pound of lint from harvest through ginning for a standard 6-row picker with the needed support equipment (e. g. module builders, boll buggies, tractors and labor), and two versions of the OBMB pickers that build their own modules, Case IH 625 Cotton Module Express (Red System) and John Deere 7760 (Green System). Analysis showed that the Red System had the lowest harvesting/operating costs per acre. Operating costs were lower for the Red System than the Green, due primarily to the lower assumed purchase price. The Red and the Green System's harvesting costs were lower than the 6RStandard picker, due to the elimination of the equipment and labor expenses associated with the boll buggies and module builders. The Red System also had lower per acre costs delivered to the gin, primarily due to the lower assumed expenses for tarps/covers and module handling as compared to the Green System. Both OBMB systems had a lower cost over the standard 6-row picker.