Abstract: An improved lubrication system for a refrigeration compressor is disclosed which lubrication system incorporates filtering arrangement for filtering lubricant supplied to a two stage lubricant pump and unique venting arrangement for venting gaseous refrigerant entrained within the lubricant. The two stage pump incorporates a vent passage in the first stage portion thereof which aids in avoiding a possible interruption of lubricant flow due to gaseous refrigerant within the first stage. A second radially extending restricted vent passage is provided in the drive shaft intermediate the ends thereof which is also designed to vent gaseous refrigerant while resisting the flow of lubricant therethrough so as to avoid priming thereof which could enable the passage to begin pumping lubricant.