Aseries of 1-alkylaminomethylnaphthols have been prepared. These compounds were readily prepared in good yields by addition of 2-naphthol to formalin and alkylamines. The hypotensive and bradycardiac effects of these compounds in normotensive rats as well as their in vitro inotropic and aortic contraction effects in isolated rat left atria and aorta have been evaluated. A higher depressor and bradycardiac activity was found for compounds substituted on nitrogen by naphthol with primary amines, i.e., ethylamine, propylamine, isopropylamine, or butylamine and with a cyclic secondary amine, i.e., pyrrolidinyl. These compounds produced biphasic changes in contractile force in isolated rat atria which was correlated to blood pressure and heart rate activity. 1-Isopropylaminomethyl-2-naphthol hydrochloride relaxed isolated rat aortic rings precontracted with high extracellular K+ (80 mM) and Ca2+ (1.9 mM). The suppressive effects of the compounds may involve a direct inhibition of Ca2+ channels. The biological activity of these compounds can be explained in terms of substitution on nitrogen.