Data from the carbon monoxide (CO) poisoning surveillance system established in mainland France are intended to guide public health initiatives and assess their impact over time and across regions. In 2007, 1,353 cases of CO poisoning were reported, involving 4,197 people. A predominance of poisonings was observed during the heating season (79.8% from January to March and from October to December). Of these incidents, 1,070 occurred accidentally in the home (3,368 people exposed). The main sources of accidental domestic CO poisoning were boilers (42.2%), water heaters (10.7%), and stoves/radiators (8.1%). The socio-professional distribution of occupants in the dwelling where the poisoning occurred varies depending on the appliance involved. In particular, the proportion of executives and professionals among CO poisonings linked to a boiler is higher than that observed in all domestic CO poisonings. In nearly three-quarters of accidental domestic poisonings, at least one contributing factor was cited. These results confirm those observed in 2006 and reinforce the need to conduct multidimensional studies on the circumstances of occurrence, in order to better understand the mechanisms involved in CO poisoning and to define homogeneous profiles of CO poisoning that could be the focus of new public health initiatives through regulatory or educational measures. (R.A.)