Crambe kotschyana is an endemic plant to Uzbekistan. Previous studies on its alkaloids were limited to brief mentions, while S-containing alkaloids are characteristic of plants in the family Cruciferae. We investigated the aerial part of C. kotschyana collected in April 2009 in Dzhizak Oblast. Total alkaloids were extracted using CHCl3 and separated via silica-gel column chromatography. Structural elucidation using IR, mass, 1H NMR, and 13C NMR spectroscopy revealed two S-containing alkaloids: one was identified as goitrin (5-vinyloxazolidin-2-thione), isolated for the first time from the genus Crambe; the other was a previously unreported geometric isomer of goitrin, named goitridin (5-vinyl-4,5-dihydrooxazol-2-thiol), which is a native alkaloid of C. kotschyana. This study represents the first systematic investigation of alkaloids from C. kotschyana, reporting the first isolation of goitrin from the genus Crambe and the discovery of the new alkaloid goitridin.