An investigation was carried out on the effect of hydraulic press parameters such as press cage diameter (D) (80, 120, and 150 mm) and wall pore diameter (H) (4, 6, and 10 mm) and expression pressure (P) on crude palm oil yield. The oil yield was found to increase with increase in cage diameter from 80 to 120 mm, after which it decreased as the cage diameter was increased to 150 mm. The volumetric oil flow followed the same pattern. The oil yield and volumetric flow increased with increase in pore size from 4 to 6 mm and decreased as the pore size increases to 10 mm. Increase in pressure form 0.5 to 1.5 MPa was observed to increase oil yield. Statistical analysis of the effect of the processing factors on oil yield indicates that the effect of all the factors were significant at 99%. It was observed that oil yield can be represented by the regression equation: Y=27.76-0.07D+0.33H+5.82P. The results of this study are useful in optimising the design of presses for palm oil extraction.