?9-Tetrahydrocannabinol (?9-THC or THC) and cannabidiol (CBD) are major constituents of the Cannabis plant that have pharmacological properties with potential therapeutic value. This invention is directed to processes for large scale isolation of these two and other cannabinoids from the Cannabis sativa plant. This is accomplished through the discovery that protected amino acid esters of the cannabinoids are easier to separate using normal phase silica column chromatography. Mild base hydrolysis of the esters regenerates the free cannabinoids in a purified form. The invention is also applicable to the isolation of other cannabinoids from Cannabis extracts.