A module for an internal combustion engine formed as a unit comprising an oil filter for lubricating oil of the engine and an oil separator for crankcase ventilation gas and which, as a whole, is attached to the engine by a flange connection with flow connections. An oil duct for oil to be filtered and an oil duct for filtered oil extend through the flange. A ventilation duct for ventilation gas and an oil return duct for separated oil also extent through the flange. A drain duct connected to the crankcase via the flange connection is provided for draining the oil filter upon a replacement of the filter element. The drain duct, the ventilation duct and the oil return duct are united in the flange connection and along at least a part of their length in the module in a single combined gas-and-oil duct.