Marcos Ayerza (born January 12, 1983, in Buenos Aires) is an Argentine retired rugby union player who played loose-head prop for the Leicester Tigers and his national team.

His Tigers debut came as a late call-up when Alex Moreno was injured in the warm-up, against Bath Rugby in September 2006.

[9] In April 2017, following medical advice regarding a back injury sustained in November 2016, Ayerza retired from professional rugby.

[11] He competed in qualifying matches for the 2007 Rugby World Cup and was capped twice during that competition, collecting a bronze medal as Argentina came third.

His family has a long tradition in horse racing, which he attributed to his Irish ancestors, and run a stud farm.