A pilot-scale ultrafiltration (UF) membrane study was conducted to investigate the influence of transmembrane pressure and crossflow velocity on the performance of a palm oil mill effluent (POME) treatment. Two commercial UF membranes, ceramic and polyvinylidene difluoride (PVDF), were used in this study. The permeate flux of both membranes decreased with filtration time until it reached steady-state values. The significant reduction in flux was observed during the fouling layer built up while the steady-state values were obtained once the fouling layer was developed. The steady-state flux increased with increasing crossflow velocity and transmembrane pressure. The percentage rejection for suspended solids, chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were also analyzed for both membranes. The crossflow velocity significantly affected the percentage rejection of COD and BOD of the ceramic membrane. Suspended solids in the permeate obtained from both membranes were almost completely absent.