ERC's tournaments are the latest addition to TG4's expanding rugby schedule which already includes the RaboDirect Pro 12 and deferred coverage of this autumn's Rugby World Cup.
The station, which pioneered television coverage of schools rugby in Ireland, also has an extensive portfolio of Gaelic games and other live sports, including the National Hurling and Football Leagues, the All Ireland Under-21 Hurling and Football Championships, the Club Championships in hurling and Gaelic football and the All Ireland Ladies Football Championship.
Sports fans can also follow the upcoming Wimbledon Tennis Championships, cycling's Tour de France and the Australian Rules League on TG4.
Pól Ó Gallchóir, Director General of TG4, said: "We are delighted to have agreed a three-year deal with ERC for coverage of both the Heineken Cup and the Amlin Challenge Cup.
"The Heineken Cup is the most prestigious European club rugby competition, and with all four Irish provinces in the tournament for the first time next season, this is a major opportunity for TG4 to further develop our rugby coverage."
Derek McGrath, ERC Chief Executive, said: "As the Heineken Cup and the Amlin Challenge Cup go from strength to strength, we are pleased to be entering into a new relationship in the Irish broadcast market."