Two new alkaloids, 4'-O-demethylhamatine (1) and ancistrotectoriline C (2), were isolated from the stems and leaves of Ancistrocladus tectorius. These two compounds represent one 5,1'-coupled and one 7,6'-coupled naphthylisoquinoline alkaloid, respectively. Their structures were elucidated by 1D- and 2D-NMR spectra and other spectroscopic studies.