Oxidative coupling of methane (OCM) was investigated in the temperature range 370-775 degreesC over Mn/Na2WO4/SiO2 catalysts with different loadings of manganese in integral-mode conditions. Na2WO4/SiO2 shows no activity at low temperature (370 degreesC), whereas Mn-doped catalyst exhibits 14% C2+ yield under similar reaction conditions, indicating that manganese plays a critical role in low-temperature methane coupling reaction. Partial pressure of oxygen in the feed also influences the low-temperature OCM activity of the catalysts.