This research paper investigates information and communications technologies (ICT) usage in an ultra-peripheral territory of the Economic Union, Réunion Island. It aims to gain a better understand of the characteristics of computerization in Réunion Island firms and how ICT use impacts on competitiveness. This research examines 118 of the largest Reunionese firms and allows us to identify several interesting factors. We have specifically examined certain characteristics such as size, age, diversification of activities or lack of diversification, status as a subsidiary of a larger firm, degree of computerization and if electronic communications influence ICT use. We also looked at certain factors that could illustrate the relationship between ICT use and firm competitiveness.