Apple scab is the main disease affecting commercial apple orchards in the VIII Region in Chile. Accurate information on the development ofthis pathogen contributes towards the development ofmore efficient disease management strategies. The objective ofthis experiment was to compare the production ofpseudothecia and asci in three apple cultivars, cvs. Mutsu, Jonagold and Macoun established in Chillán (36°34'S; 72º06'W). Pseudothecial productivity was higher in cv. Mutsu only in the first assessment. Mature asci was observed from August 18 to October 6 and its maximum production per pseudothecium, observed on August 25, was similar in the three cultivars, with 61 asci in Mutsu, 66 in Jonagold and 71 in Macoun, corresponding to 67% of the total asci per pseudothecium in Mutsu and approximately 80% in the Jonagold and Macoun.