Cadmium (Cd) is a widely spread environmental contaminant that exerts varied toxicity, including established carcinogenetic activity. Due to its long biological half-life (more than 10 years), chronic exposure and accumulation of Cd can give rise to a variety of toxic phenomena in the bones, the urogenital system and in the lungs. This short review focuses on the data that document the carcinogenic properties of Cd correlated with the induction of lung cancer. Smoking and exposure to Cd compounds at work are the main sources of Cd inhalation. The mechanisms involved have not been completely elucidated, but the oxidative and deregulating actions of Cd on certain proteins and enzymes of the exposed lung cells are thought to play a major role. Pneumon 2008; 21(2):172–177