Technical Abstract: `Bartlett¿ and `d¿Anjou¿ pears treated with 300 nL L-1 1-methylcyclopropene (1-MCP), did not soften to eating quality within 7 d, a desirable ripening period. In this research, a preconditioning method was evaluated as a means to regenerate ripening ability of pears prior to marketing. Fruit treated directly after harvest with 300 nL L-1 1-MCP at 20 °C for 24 h were stored at -1 °C in regular air (RA) or a controlled atmosphere (CA). After 2-9 months of storage, fruit were preconditioned with 9 combinations of temperature (10, 15 or 20 °C) and time (5, 10 or 20 d) for each cultivar, storage atmosphere and storage duration. Preconditioned fruit were assessed for ripening ability following shelf life for 14 d at 20 °C. The ripening ability of 1-MCP-treated `Bartlett¿ fruit recovered in response to many preconditioning combinations of 10-20 °C for 10-20 d as indicated by a decrease in flesh firmness to 27 N or lower. The preconditioning combinations of higher temperature and/or longer time accelerated the ripening response of the fruit. For `d¿Anjou¿ pears, no preconditioning combination was used that resulted in regenerating ripening of fruit. However, when 1-MCP dosage was < 50 nL L-1, `d¿Anjou¿ pears ripened in an extended shelf period, or within 7 d if the dosage was < 25 nL L-1 at 20 °C after 4 month storage in RA, although superficial scald was not completely controlled at these low dosages. Regeneration of ripening was concomitant with a substantial increase of ethylene productions. The results suggest that preconditioning regimes are cultivar, storage atmosphere and time dependent.