The Neotropical cornstalk borer, Diatraea lineolata (Walker) 1856 (Lepidoptera: Crambidae), is a pest of economic importance for cultivation of maize, Zea mays L., in Mexico. Digonogastra kimballi Kirkland 1989 (Hymenoptera: Braconidae) was identified as a gregarious ectoparasitoid of fifth-instar larvae of D. lineolata. Parasitism was low, 0.39 to 0.98% on cornstalk borers during three maize planting seasons. This is the first record of D. kimballi parasitizing D. lineolata larvae in maize at Macuspana, Tabasco, which broadens the distribution of the species in Mexico.