All post-mortem medicolegal reports issued by Jordan University Hospital (JUH) during the period 1978-96 were reviewed. Carbon monoxide (CO) as a silent killer was responsible for 31.5% (n = 110) of poisoning fatalities. These were due to unintentional exposure to CO sources in confined spaces (bedrooms (24.6%), worker lodgings (23.6%) and bathrooms (16.4%), and without the victims being aware of CO hazards. Sixty-five per cent of CO fatalities occurred during December to February and 30% of the cases involved the age group 20-29 years, followed by the age group 30-39 years (20%). Non-Jordanians constituted 50% of CO fatalities and Egyptian workers accounted for 78%. Being unaccustomed to cold climates, and on low incomes, they had been using simple and unsafe heating devices. Many of these deaths could have been prevented. Safety educational campaigns to increase awareness of the general population of CO sources, their hazards and how to avoid them should be held continuously during the cold months of the year. All health and safety sectors are advised to be involved.