Abstract: Hetrazan,1-diethylcarbamyl-4-methyl piperazine citrate,is considered at pre- sent to be the most effective drug for the treatment of Filariasis.Although it can be determined indirectly by the Kjeldahl method with high accuracy,but the pro- eedure of this method is time-consuming.In this paper a method based on the principle of nonaqueous titration has been described.Both of the base and acid components of the drug can be titrated in nonaqueous solvents,the former with perehloric acid in glacial acetic acid using crystal violet as indicator and the latter with sodium methoxide in methanol-benzene mixture using thymol blue as indicator, however,the acid titration is more satisfactory than the base titration.This method can also be used for the assay of Hetrazan tablets.