In Elqui Valley (29° - 30° lat. S), IV Region of Chile, a study was carry out on potato between 1993 and 1997, to determine the composition, seasonal abundance, other hosts and parasitism on leafminers, Liriomyza (Diptera: Agromyzidae). The results indicated that Liriomyza huidobrensis (Blanchard), is the dominant species on potato with two population peaks, in fall and spring. Leafminer also affects beans, celery and peas. There is a complex of leafminers parasites, able to reach high levels of parasitism during summer months, regulating the leafminer population.