A modification of the benzene synthesis method for tritium analysis by liquid scintillation counting is suitable for limited production of hydrologic samples and has a lower detection limit of 10 TU (1 TU = 10⁻¹⁸ T/H). Procedures are described for elimination of sulfide quenching of the benzene and optimization of the acetylene‐benzene conversion. Tritium isotopic fractionation is constant during benzene synthesis with a loss of (19.3 ± 0.2)% of the water sample tritium activity. Cross checks with other laboratories agree within counting statistical error.