The Neotropical cornstalk borer, Diatraea lineolata (Walker), is a pest of economic importance in maize, Zea mays L., in Mexico. The objective was to evaluate natural parasitism by Apanteles diatraeae Muesebeck on D. lineolata larvae during four ‘Mejen’ maize-growing seasons at Tabasco, Mexico. Parasitism by the braconid A. diatraeae on D. lineolata larvae was relatively low, from 0.29 to 2.8%. Of a total of 15 parasitized larvae, 46.6% were 3^rd instar, 26.7% 4^th instar, and 26.7% 5^th-instar larvae. A. diatraeae is a gregarious endoparasitoid, with an average of 57.1 wasps emerging per parasitized larva and a sex ratio of 1:0.44 (female:male). The braconid should be studied in greater detail to know more about its interrelationship with its host during phenological stages of the crop, before physiological maturity of maize plants.