A logistic regression model was built to describe the effect of picking time and the most relevant commercially applied storage factors on the incidence of core breakdown in pears (Pyrus communis L. cv. Conference). The statistical analysis showed that the probability of core breakdown depended on several variables in a more complicated way than assumed before. In general, more mature fruit, stored at lower O-2 and higher CO2 concentrations, at a higher temperature and for longer times are more susceptible to core breakdown. However, delaying the controlled atmosphere (CA) conditions for 21 days decreased the core breakdown incidence efficiently even for late-picked fruit. Together with a proper delay of CA, a sufficiently high O-2 concentration during CA was most important. The model was validated with data of 16 orchards gathered over five harvest seasons in two countries which gives it a wide validity range and a high practical relevance. (C) 2002 Silsoc Research Institute. Published by Elsevier Science Ltd. All rights reserved.