At Steinhart Aquarium between December 2001 and July 2003 four litters of Whitetip reef sharks Triaenodon obesus were born to two ♀♀ producing at least 13 pups. Mean gestation period, estimated from the first appearance of mating wounds on the ♀ to parturition, was 387 ± 33·7 days (mean ± SD; n= 3). On three occasions, ♀♀ were caught and transferred from the exhibit to an isolation tank for the safety of both the pregnant ♀♀ and neonates. Ultrasound examination was carried out and blood samples taken during two pregnancies: at day 272 and day 288 of gestation for ♀1 and ♀2, respectively. An underwater video-monitoring system recorded the birth of one litter of four pups. The total time from when the first pup's tail was observed emerging from the ♀'s cloaca to the full emergence of the final pup was 51 minutes: time between the full emergence of each pup was 10–13 minutes. Adult ♀♀ were returned to the exhibit on the day they gave birth and the mean time between parturition and next observed mating wounds was 95·7 ± 52·2 days (mean ± SD, range 57–155 days, n= 3).