In Mexico’s high valleys, from 2200 to 2600 meters above sea level, use of improved varieties is low (6%). And it would be convenient that in addition to the varieties and hybrids which are promoted through government programs (Kilo x Kilo), to include other non conventional varieties for low potential areas which are not presently covered, allowing farmer to increase their own seed. One possibility to improve corn land races is by crossing them with hybrids to improve their characteristics and increase productivity. In 1997 nine land race corn varieties where crossed with a single hybrid of medium height and good cob position. The product was evaluated during the 1998 spring-summer growing season and compared to its parents and five commercial varieties. The results show that non convention hybrids showed higher yields than the parent land races, and eight out of nine where numerically superior, anywhere form 2 to 40%, to H-40. The best commercial check was H-50 with 5.5 tha-1, which was surpassed by 14.9% by the best non conventional cross (6.3 tha-1). This demonstrates that non conventional hybrids is a good alternative to increase yield and improve agronomic characteristics of high land corn land races.