This paper deals with the existence and search of properly edgecolored paths/trails between two, not necessarily distinct, vertices s and t in an edge-colored graph from an algorithmic perspective. First we show that several versions of the s-t path/trail problem have polynomial solutions including the shortest path/trail case. We give polynomial algorithms for finding a longest properly edge-colored path/trail  Sponsored by French Ministry of Education  Sponsored by Conselho Nacional de Desenvolvimento Cient							
						
							
					 															
					A. Abouelaoualim, Kinkar Chandra Das, L. Faria, Ya