Disclosed is a drilling mud degassing apparatus which comprises a tank wherein a plurality of vertically spaced partitions are disposed for flowing drilling mud deposited on the uppermost partition consecutively across the upper surfaces of the partitions. The uppermost and lowermost partitions have peripheral edges spaced from the wall of the tank and an intermediate partition is provided which has a periphery engaging the wall of the tank and a central opening such that mud is flowed alternatively radially outwardly and radially inwardly in traversing the tank. The apparatus further includes a pump assembly which draws mud from a mud pit and forces the mud in a jet on to central portions of the upper partition. Tubes extending through a cover portion of the tank and having openings into chambers between the partitions discharge gas from the tank and mud is discharged from the tank via a mud outlet adjacent the lower end of the tank.
