Smoking, drinking and drug use appear to be more prevalent among boys than girls and it is also interesting to note that the rate of smoking, drinking and drug use among boys increases when they attend a mixed sex school. The main objective of this study was to identify the consumption patterns and trends of alcohol , tobacco and illicit drugs among secondary school students in Mauritius. It also areas that may be useful to policy makers and parents, such as the ways and means used in purchasing the substances under investigation.