The invention shows an improvement in the lubrication of bearings and shaft seals of screw compressors for refrigerants with oils soluble in refrigerants. A typical application results, for example, for ammonia with polyalkylene glycol soluble therein. Due to the fact that a partial oil flow is taken out of the oil flow returned to the screw compressor at an intermediate pressure prior to a pressure reduction to nearly suction pressure of the compressor and conveyed via a vapor separation container, substantial proportions of the dissolved refrigerant can be fed in at an intermediate pressure connection on the compression path of the screw compressor. Correspondingly more advantageous are the lubrication properties of the remaining partial oil flow at the lubrication connection, and the disadvantages of pressure collapse or foam conveyance at an oil pump are absent, since no oil pump is required with a suitable intermediate pressure.