Clerodendrum phlomidis Linn. f. of the family Lamiaceae is an important and well known medicinal plant in Ayurveda and Siddha system of medicines. To ensure identity, quality of the plant material and considering the wide therapeutic application of L-DOPA, lupeol and β-sitosterol, the present study was planned to quantify these marker constituents by TLC method. The amount of L-DOPA, lupeol and β-sitosterol quantified from the leaves of C. phlomidis were 0.06806, 0.01733 and 0.06324 % w/w, respectively. This TLC procedure may be used effectively for identity, quality evaluation as well as quantitative determination for this plant or its derived products.