Previous research has demonstrated that storage of dry-sale Asiatic hybrid lily bulbs in a 1% O 2 atmosphere can improve quality and shelf-life (22–24 °C) of certain cultivars compared with storage in air, indicating a possible application for modified atmosphere packaging (MAP) [Legnani, G., Watkins, C.B., Miller, W.B., 2004a. Low oxygen affects the quality of Asiatic hybrid lily bulbs during dry sale storage and subsequent forcing. Postharv. Biol. Technol. 32, 223–233]. The success of a MAP system would be dependent on the tolerance of lily bulbs to the elevated CO 2 levels that would occur within the MAP; therefore, the effects of warm (22 °C) bulb storage with elevated CO 2 atmospheres (4%, 8%, or 16%) in combination with 1% O 2 or air on growth and development of three cultivars of Asiatic hybrid lily bulbs have been investigated. Elevated CO 2 in combination with 1% O 2 had no effect on shoot elongation prior to transplanting, flower development, and height at flowering of ‘Colosseo’ and ‘Vermeer’ bulbs. Leaf area of ‘Vermeer’ bulbs stored in 1% O 2 was reduced by increasing CO 2 concentrations, but was still greater compared with plants stored in air or 21% O 2 + 16% CO 2. Elevated CO 2 in combination with 1% O 2 had a beneficial effect on growth and development of ‘Vivaldi’, inhibiting shoot elongation prior to transplanting, increasing flower bud number, height at flowering, and leaf area, while lessening the severity and occurrence of flower abnormalities. Compared with air, storage of bulbs in 21% O 2 + 16% CO 2 showed benefits for all cultivars, inhibiting shoot elongation prior to transplanting and flower bud abortion, while increasing height at flowering and leaf area. Flower bud number was decreased slightly and flowering was delayed by 10–14 days depending on cultivar. Elevated CO 2 did not affect bulb respiration rate but it did increase ethylene production. Possible developmental effects of increased ethylene production under elevated CO 2 are discussed. The data demonstrate that Asiatic hybrid lily bulbs can tolerate the high CO 2 concentration that would occur in a modified atmosphere package (MAP) designed to extend shelf-life by lowering the ambient O 2 concentration.