A proportional counting system for radiocarbon dating is described in this article. The CO2counter has an effective volume of 1.2 liters and operates at a pressure of 2 atm. The total background is 1.10 counts/min and the standard net count on recent carbon is 16.0 counts/min. Maximum measureable age is 43 000 years. The end terminals of the counter have a few original details which serve to reduce inactive counter volume and the end effects. The ground capacity of the center wire has been reduced to a very small value (10 pF). Anticoincidence shielding is provided by a multiple‐anode proportional counter. It is filled with C3H8to a pressure of 1.3 atm and can operate continuously for at least one year without refilling. The counter walls of the ring counter and the CO2counter are connected together and supplied with the same high voltage. Shielding against &ggr; rays is provided by a 22‐cm‐thick iron shield around the counting unit, and by a shell of 3.5‐cm old lead between the CO2counter and the ring counter.