Three new isosteroidal alkaloids, karelinine (1), 5-epikarelinine (2), and 27-epiebeienine (3), were isolated from the bulbs of Fritillaria karelinii by column chromatography and semipreparative HPLC (high performance liquid chromatography), together with three known ones, ebeienine (4), persicanidine B (5), and heilonine (6). Their structures were identified by MS, 1D/2D NMR, and single-crystal X-ray diffraction. Compound 1 is a 5 beta-jervine isosteroidal alkaloid featuring a cis-fused A/B ring moiety, rarely found in the Fritillaria genus. Compounds 1 and 2 also represent the first jervine alkaloids with a 15 alpha-hydroxy group from this genus.