The tiger shark Galeocerdo cuvier is a common predator in tropical oceans although its biology is still not well documented, especially in the western Indian Ocean. We report the first observation of a pregnant tiger shark captured at Reunion Island in November 2012. A total of 42 embryos without external yolksacs, measuring 750-846 mm in total length, were found in the two uteri. The sex ratio was nearly 1:1 and males and females did not differ in size or weight. Although the embryos were fully formed, the teeth had not yet erupted through the gums, suggesting that birth would take place a few weeks later. This information is in agreement with observations made in other locations, including the limited data available for this region, suggesting that mating occurs in late winter and parturition in summer