Flux decline and recovery of UF process used in concentrating milk at different operational pressures were studied. Filter medium resistance during filtration and cleaning was estimated from the experimental data. Energy consumption during filtration and cleaning processes were estimated. Regarding the flux behavior, retentate and permeate fluxes declined with time at different operational pressures during filtration, on contrary, flux during cleaning increased with time at all pressures studied. Filter medium resistance increased linearly with time of filtration at different operational pressures during concentration. It increased during the first 40 min of cleaning process and decreased with time to reach the minimum resistance at the full flux recovery. The total energy consumed for filtration ranged from 50.08 to 62.54 kJ/L of retentate, while it ranged from 18.18 to 21.65 kJ/L of permeate. The energy consumed for cleaning ranged from 87.08 to 107 kJ at different operational pressures.