In the absence of a provincial radon policy, the Public Health Branch of the Quebec Ministry of Health and Social Services (MSSS) commissioned the Quebec National Institute of Public Health (INSPQ) to conduct a province-wide assessment of this issue. The primary task of the working group that was formed was to assess the health risks attributable to residential radon in Quebec through a risk analysis approach. This article outlines, among other things, the main points addressed in the 2004 report published by this working group. It first describes the radon concentrations measured in homes across Quebec. It then presents a risk analysis based on one of the models developed by the BEIR VI committee. According to this analysis, radon accounts for approximately 10% of lung cancer deaths, or about 430 of the 4,101 deaths attributable annually in Quebec to this type of cancer. It subsequently examines the various intervention strategies implemented around the world. He then analyzes the intervention strategies that are feasible for Quebec and the recommendations the working group derived from this analysis, particularly two of them that were deemed the most promising: the adoption of preventive measures in the Quebec Building Code and radon testing in public buildings (schools, daycare centers, etc.). Finally, he outlines the work carried out at the federal level on revising the Canadian guideline, which had been set at 800 Bq/m³ since 1988. This guideline has been called into question, and the Federal Radiation Protection Bureau has proposed to the Canadian Minister of Health that it be lowered to 200 Bq/m³. It is expected that this measure will be announced in the spring of 2007. (R.A.)