A sensitive and simple high-performance liquid chromatographic (HPLC) method for the assay of 6,11-dihydro-2-methoxy-5H-benzo[a]carbazole (1) and 6,11-dihydro-2-methoxy-11-[2-(1-piperidinyl)]ethyl-5H-benzo[a]carbazole (2) was developed. The procedure is based on the use of the reversed-phase high-performance liquid chromatographic (RP-HPLC) method with UV detector. Each analysis required no longer than 11 min. A linear relationship between the concentration of both the drugs and the UV absorbance at 254 nm was obtained. This linearity was maintained over the concentration ranged from 5 to 80 μg/ml. The detection limits were found to be 1.6 and 0.7 ng for compounds 1 and 2. The quantitation limits were found to be 5.3 and 2.5 ng for compounds 1 and 2, respectively. For recovery studies, several determinations were carried out. Recovery values ranged from 98 to 102.1% for compound 1 and from 98.4 to 101.6% for compound 2. Method precision was also evaluated and RSD% found was less than 2%. This method was applied without any interference from degradation products.