The Cartago Agrarian Union Party () is a political party in Cartago Province, Costa Rica.
The party was founded in 1969 by Juan Guillermo Brenes Castillo. It first contested a general election in 1970, but received only 0.5% of the vote and failed to win a seat. In 1974 support for the party more than doubled, receiving 1.2% of the vote and winning its first seat. Despite seeing its share of the vote drop to 1%, the party retained its seat in the 1978 elections. However a further slump to 0.8% in 1982 saw the party lose its parliamentary representation.
It regained a seat in the 1986 elections, receiving 1.2% of the national vote. The seat was retained in elections in 1990 and 1994, but a loss of support in the 1998 elections saw its share of the vote drop to 0.5%, resulting in it losing its solitary seat. A similar result in 2002 saw the party remaining seatless.