The results of a study of new scorpion material, comprising nine species collected during a recent field trip to Trinidad and Tobago, are presented. The Trinidad population of Tityus discrepans (Karsch 1879) is described as a new species, Tityus tenuicauda, endemic to Trinidad, and more closely related to Tityus arellanoparrai González-Sponga 1985 than T. discrepans, both from Venezuela. A key to the identification of the three species is provided. New records are provided for Ananteris cussinii Borelli 1910, Microtityus rickyi Kjellesvig-Waering 1966, Tityus clathratus C.L. Koch 1844 and Tityus melanostictus Pocock 1893. Specimens of Microtityus collected on Tobago provide evidence for the synonymy of Microtityus starri Lourenço & Huber 1999 with M. rickyi. Previously unreported ecological observations are presented, including the burrowing biology of Broteochactas laui Kjellesvig-Waering 1966, and the microhabitat of Chactas raymondhansorum Francke & Boos 1986, which is apparently not restricted to water-filled spaces between the leaf sheaths of bromeliads.