The use of illegal drugs is an issue that has raised both international and national concern. This paper deals with the descriptive results from a household survey of the use of marijuana and cocaine in a population aged from 15 to 64 in Santiago, Chile. Life prevalence of use was 19.0% for marijuana, 4.5% for cocaine, and 2.2% for coca paste; annual prevalence was 5.4%, 1.8% and 0.8%; and last month prevalence was 3.2%, 0.7%, and 0.3% for each substance. Median age for initial use was 17.9 years for marijuana and 20.3 for coca paste. Those surveyed considered the use of paste to be the most risky, followed by cocaine and marijuana. Higher ratings of dependency were observed in the users of coca paste. Rates of use were similar to those of previous national and regional studies, but considerably lower than those of developed countries