This study investigated the effects of preharvest spraying with Pichia guilliermondii on postharvest natural decay of cherry tomato fruit, and evaluated the quality attributes during storage. Preharvest spraying with P. guilliermondii significantly decreased the decay index. Moreover, the efficacy of this biological control was positively correlated with spraying frequency. However, preharvest spraying with P. guilliermondii and spraying frequency did not significantly affect fruit quality attributes regardless of whether the cherry tomato fruit was grown or stored after harvest. This observation indicates that preharvest spraying with P. guilliermondii does not influence the quality attributes of the fruit. In addition, the activities of peroxidase (POD), phenylalanine ammonia-lyase (PAL), and β-1,3-glucanase increased in all P. guilliermondii treatments, suggesting a positive correlation with spraying frequency. The results suggest that cherry tomato fruit is capable of responding to preharvest spraying with P. guilliermondii, which can activate its defensive enzymes and thus induce host disease resistance.Key words: Preharvest, Pichia guilliermondii, cherry tomato fruit, decay, quality