The contents of ginkgolides were determined in the leaves of male and female Ginkgo biloba from late spring until mid-autumn. Ginkgolides were detected during the whole growing season in the leaves of each tree. Ginkgolides content was low in late spring, gradually increased to reach a maximum in august and decreased thereafter. The male trees have two or three times higher ginkgolides content than the female trees. Comparing our results with that of previously reported values, the sexual variation of ginkgolides content seemed not to be genetic.