The time after harvest is characterized by physiological changes in the fruit that favor the occurrence of postharvest diseases, which are often observed only after sale. As a result, the damage resulting from the action of quiescent pathogens can be underestimated. From November to April of the years 2009/2010 and 2010/2011, a survey was conducted to quantify the postharvest diseases in 'Kumagai' and 'Pedro Sato' guavas at two large wholesale markets in Brazil. The incidence of postharvest diseases differed significantly between the two cultivars evaluated. The most frequent postharvest diseases for 'Kumagai' guavas were anthracnose, black spot and fusicoccum rot, ranging in incidence from 23.6 and 31.6%. For 'Pedro Sato' guavas, the most frequent postharvest disease was anthracnose, with an incidence of approximately 72.3%.