Toddalia asiatica Linn. is an important medicinal plant belonging to the family Rutaceae. The plant is well known for its antimalarial activity, which has been attributed to the presence of benzophenanthridine alkaloid nitidine in the roots of plants. A simple, rapid, sensitive, accurate, repeatable and robust HPTLC method has been developed and validated for the quantitative determination of nitidine in the dried roots and plant tissue culture extracts of T. asiatica. Nitidine was estimated at 332 nm by densitometry using Silica gel 60 F₂₅₄ as stationary phase and chloroform:methanol (7:1, v/v), and as mobile phase. Linearity was observed in the concentration range of 25 -200 ng/spot for nitidine. The limit of detection and limit of quantitation were found to be 0.026 and 0.086 ng/spot respectively for nitidine. Developed method was validated according to the ICH guidelines with respect to precision, accuracy, specificity and robustness. The technique has been applied for the first time for the estimation of nitidine in roots and plant tissue culture extracts of T. asiatica. Statistical analysis data indicate the accuracy and reliability of the method.