tOzone treatments are used to preserve quality during cold storage of commercially important fruitsdue to its ethylene oxidizing capacity and its antimicrobial attributes. To address whether or not ozonealso modulates ripening by directly affecting fruit physiology, kiwifruit (Actinidia deliciosa cv. ‘Hayward’)were stored in very low ethylene atmosphere at 0◦C (95% RH) in air (control) or in the presence of ozone(0.3 L L−1) for 2 or 4 months and subsequently ripened at 20◦C (90% RH) for up to 8 d. Ozone-treatedkiwifruit showed a significant delay of ripening during maintenance at 20◦C, accompanied by a markeddecrease in ethylene biosynthesis due to inhibited AdACS1 and AdACO1 expression and reduced ACCsynthase (ACS) and ACC oxidase (ACO) enzyme activity. Furthermore, ozone-treated fruit exhibited amarked reduction in flesh softening and cell wall disassembly. This effect was associated with reducedcell wall swelling and pectin and neutral sugar solubilization and was correlated with the inhibition ofcell wall degrading enzymes activity, such as polygalacturonase (PG) and endo-1,4--glucanase/1,4--glucosidase (EGase/glu). Conclusively, the present study indicated that ozone may exert major residualeffects in fruit ripening physiology and suggested that ethylene biosynthesis and cell walls turnover arespecifically targeted by ozone.