Pressing operation is an interesting subject of discussion as it involves two crucial process losses parameters namely, oil loss and broken nuts. Though zero loss in palm oil milling is impossible, this does not mean that effort should not be given to find ways in reducing it even though the losses is already within specification. It must be noted that higher process losses will lead to higher operating cost and eventually be used as indicator that the processing is not being carried out efficiently. Digester operation, main screw speed, pressure cone setting and maintenance are among the crucial factors that affect the pressing operation. In addition to that, operator’s effort and his responsiveness on mash and crop condition are crucial for achieving good press operation. This article reviews few variables that affect the screw press operation performance.