Abstract: The detection of leaks in tubes, particularly cooling tubes in a steam condenser, is disclosed herein. In accomplishing this, a discrete amount of helium or similar tracer gas is initially directed into the front ends of the tubes while, at the same time, this gas is prevented from escaping into the ambient surroundings. Thereafter, the gas is drawn or otherwise moved by positive force through the tubes to the backends thereof, causing a portion of the gas to escape through leaks in the tubes, if any such leaks exist. The escaping gas, if any, is detected to indicate the presence of a leak and, at the same time, the non-escaping tracer gas reaching the backends of the tubes is captured and directed to a remote location.