An improved reverse phase high performance liquid chromatography (HPLC) procedure has been described to estimate azadirachtin-A content in crude methanolic extracts of neem seed kernels using valley-to-valley integration techniques. The present paper highlights a detailed study of extraction, estimation, and purification of azadirachtin-A present in neem seed kernels. We also present, herein, our results of Soxhlet extraction of Aza-A from the defatted neem seed cake as a function of time, which is found to be more efficient than the conventional extraction procedure. [ABSTRACT FROM AUTHOR]