Changes in the fatty acid composition at different stages of development in the mesocarp of medlar (Mespilus germanica L.) fruit was studied by gas liquid chromatography (GLC). Twenty different fatty acids were identified, 10 of which were saturated and 10 unsaturated. The total fatty acid content of the fruit changed throughout development, reaching a maximum value of 6,121 mug/g dry wt by mid-August and thereafter declining to a value of 2,583 mug/g dry wt in the fully ripe fruit (October). Linoleic acid (C 18:2n-6) contributed most to the percent composition of the total fatty acids in the lipid extract at all five stages of development, contributing 51% of the total fatty acid content (1,291.7 mug/g dry wt) in fruit harvested in October. Even in the ripest fruit, alpha-linolenic (18:3n-3) acid contributed 13.5% to the total fatty acid content at 359.9 mug/g dry wt. The combined levels of both linoleic acid and linolenic acid contributed similar to65% of the total fatty acids at 1, 652 mug/g dry. wt.