A novel high-performance liquid chromatographic (HPLC) method is described for the determination of the alkaloid cuscohygrine [1,3-bis(1-methyl-2-pyrrolidinyl)-2-propanone] in air-dried leaves ofErythroxylum cocavar.coca.The analysis was performed on a weak cation exchange HPLC column using a mobile phase consisting of MeOH: 0.05 M KH2PO4, pH 7 (75:25, v/v) and with UV detection at 220 nm. Cuscohygrine content was determined as 0.21–0.23% inE. cocaleaves.