A cytological study of Venturia inaequalis has revealed that only one meiosis occurs in the ascus, and that the haploid number of chromosomes is seven. Most asci originate through typical hooks, but in a number of perithecia these croziers are absent, and large budding cells give rise to small ascus-shaped structures. Variations in nuclear stainability were observed among perithecia at the same stage of maturity. Attempts were made to characterize the seven chromosomes.