A laboratory handling tritium requires a large variety of procedures for the assay of tritium concentrations over a very wide range (10−9 Ci/m3a to 106 Ci/m3). The measurement of tritium can be conveniently categorized into four levels from very low concentrations to very high concentrations (up to 100% T2). This paper will describe in detail the monitoring and analytical procedures used, as well as operational experience with the various equipment, in the CRNL Tritium Laboratory.a1 Ci = 37 GBq