The maturity at harvest of Tommy Atkins mango (Mangifera indica L.) was found to have an important effect on the development of fruit quality when ripened at 25°C. Fruits harvested at the mature and half-mature stages developed good quality characteristics, but immature fruits showed only limited changes during ripening. Treatment with either 1.0 ml litre-1 ethylene or acetylene initiated ripening at all three maturity stages, although ripening remained incomplete in immature fruits. Mature fruits ripened faster than both half-mature and immature fruits when not treated with exogenous ethylene or acetylene. The ripening rate of fruit in successive harvests over a four-week period increased during the season. Acetytene treatment appeared more effective with early season harvests, notably for peel colour development; the overall effect was less apparent in late season fruit. If harvesting of immature fruit is avoided, both ethylene and acetylene treatments at 1.0 ml litre - l for 24 h at 25°C improve the uniformity in quality by inducing simultaneous ripening and have potential in the commercial ripening of mango.