Group 7-12 transition-metal complexes serve as effective catalysts for the regioselective intramolecular hydroamination of aminoalkynes having the general formula RCtC(CH 2 ) n -NH 2 (n ) 3, R ) H, Ph; n ) 4, R ) H) and of 2-(phenylethynyl)aniline. Primary products are pyrrolidines and piperidines bearing an R-alkylidene functionality and 2-phenylindole, respectively. Isomerization yields the corresponding pyrrolines and 1,2-dehydropiperidines. The catalytic properties of the transition-metal complexes depend on the appropriate choice of ligand, solvent, temperature, and counteranion. Principles for identifying the most active transition-metal catalysts for the hydroamination of alkynes and for optimizing the reaction conditions are developed. The X-ray crystal structure of one catalyst, [PdCl(triphos)](CF 3 -SO 3 ), has been determined.