This three-part article examines the histologic and morphologic basis for stenotic and purely regurgitant tricuspid valves. In Part I, conditions producing tricuspid valve stenosis were reviewed. In Part II, conditions producing pure tricuspid regurgitation are discussed. In contrast to the relatively few causes of tricuspid stenosis, the causes of pure (no element of stenosis) tricuspid regurgitation are multiple. Some of the conditions producing pure regurgitation include floppy tricuspid valves, infective endocarditis, papillary muscle dysfunction, rheumatic disease, and Ebstein's anomaly.