Six morphinane alkaloids, cephasamine (3), cephakicine (4), tannagine (6), 14-episinomenine (7), FK-3000 (8), and sinoacutine (9), and five hasubanane alkaloids, cephatonine (5), cepharamine (10), aknadinine (11), aknadicine (12), and aknadilactam (13), were isolated from the tuber of Stephania cepharantha Hayata (Menispermaceae) cultivated in Japan. Three of these (3-5) were new alkaloids. Structures were spectroscopically determined by comparison of their 1H and 13C NMR data with that of cephamonine (1), cephamuline (2), and other known alkaloids (6-13). In a previous paper,1 we have reported the isolation and structural determination of two new morphinane alkaloids, cephamonine (1) and cephamuline (2), from the tuber of Stephania cepharantha Hayata (Menispermaceae)2 cultivated in Japan. In further investigation of the alkaloidal constituents of this plant, we have isolated two new morphinane alkaloids, cephasamine (3) and cephakicine (4), and one new hasubanane alkaloid, cephatonine (5), together with four known morphinanes, tannagine (6),3 14-episinomenine (7),4,5 FK-3000 (8),6,7 and sinoacutine (9),8,9 and four known hasubananes, cepharamine (10),10,11 aknadinine (11),12,13 aknadicine (12),13 and aknadilactam (13).13,14 This paper deals with the isolation and structural determination of 3-5.