The recent acceleration in hydrogen production's R&D will lead the energy transition. Low temperature polymer electrolyte membrane electrolysis (LT-PEME) is one of the most promising candidate technologies to produce hydrogen from renewable energy sources, and for synthetic fuel production. LT-PEME splits water into hydrogen and oxygen when the voltage is applied between anode and cathode. Electrical current forces the positively charged ions to migrate to negatively charged cathode through PEM, where hydrogen is produced. Meanwhile, oxygen is produced at the anode side electrode and escapes as a gas with the circulating water. The effects of clamping pressure (P-c) on the LT-PEME cell performance, polarization resistances, and hydrogen and water crossover through the membrane, and hydrogen and oxygen production rate are studied. A 50 cm(2) active area LT-PEME cell designed and manufactured in house is utilized in this work. Higher P-c has shown higher cell performance this refers to lower ohmic and activation resistances. Water crossover from anode to cathode is slightly decreased at higher P-c resulting in a slight decrease in hydrogen crossover from cathode to anode. Also, the percentage of hydrogen in the produced oxygen at the anode side is significantly reduced at higher P-c and at lower current density. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.