Agulla, who played 48 times for the Leicester Tigers where his commitment and determination as well as his bulldozing runs led to him winning the 2011/12 Tigers fans' Player of the Aeason and Try of the Season awards.
An intelligent and powerful player with great footwork and pace, he made his international debut in 2005 against Samoa and has since represented his country at the 2007 and 2011 Rugby World Cups, with the Pumas finishing third in 2007.
Bath will be playing in the Amlin Challenge Cup next season and will be strong contenders to qualify from Pool 4 which includes Agen, Cammi Rugby Calvisano from Italy and Bucharest Wolves.
Bath Rugby Head Coach, Gary Gold, said: "We're really excited to have Horacio join Bath Rugby for the new season and are looking forward to him getting stuck into training with the rest of the squad. He's a very good player who is able to play two positions at a high level which brings great diversity and strength in depth to the team. We believe his exposure playing for Argentina in the new Rugby Championship format against the All Blacks, South Africa and Australia will further develop him as a player and Bath Rugby can only benefit from that."