The partial oxidation of methane (MPO) to formaldehyde by molecular oxygen has been studied in the temperature range 840-900 K and atmospheric pressure in a continuous gas recycle reactor separator using a supported V2O5-SiO2 catalyst. The recycled gas passes continuously through a trap unit in the recycle loop and thus formaldehyde is protected from further oxidation. In this way high (up to 56%) selectivity is maintained for methane conversions up to 89%. This leads to formaldehyde yields up to 50 versus 2% for single pass operation. The effect is discussed of V2O5 catalyst loading, temperature, space velocity, inlet CH4 to O-2 ratio and recycle flowrate on formaldehyde selectivity and yield.