From 1986 to 2002, 16,618 twin babies have been reported to FIVNAT. Mean length of gestation was 36.74 weeks. The mean weight was 2413 g and mean height 46 cm. The proportion of prematurity under 28 weeks of amenorrhea was 1.17% and under 33 weeks: 7.78%. These data are similar to those reported in the French AUDIPOG Report.