At the Experimental Station La Platina, belonging to the Institute of Agricultural Research (INIA, Santiago, Chile) two trials were carried out during 1985/86 and 1987/88. The purpose was to evaluate the resistance of 28 alfalfa varieties to the stemand bulb nematode (Ditylenchus dipsaci) under greenhouse condition. On both trials, INIA varieties Rayen-INIA, Palihue-INIA and Huinca-INIA (the latter evaluated only one season) were highly resistant to the stem nematode. Varieties such us talent, WL-522, WL-314, Apalachee, Synt U.C., Pierce, California 55, WL-324 and Pioneer 5929 were to be found resistant. WL-519, California 60, Nevada Synt XX, Criolla, Hunterfield, Springfield, C-87-55, Seguel, Pioneer 581 and Siriver were moderately resistant. Variety Cuf 101 was susceptible.