An investigation was made of the effects of a short and acute exposure to cigarette smoke on the capacity of alveolar macrophages from mice to carry out all stages of the phagocytic process. Cigarettes were commercial 80 mm filter cigarettes that contained 17 mg of tar and 1.1 mg of nicotine per cigarette. The acute exposure of each animal was with one cigarette for 15 min (until the complete consumption of the cigarette) in a box-shaped plastic chamber, 7732 cm3 vol and 450 cm2 floor surface, with a 3 cm dia airhole. Animals were sacrificed immediately after the exposure to the smoke. The results showed no differences either in the adherence or in the chemotaxis capacities between alveolar macrophages from control mice and from mice exposed to cigarette smoke. However, there was a significant decline both in attachment capacity and in ingestion capacity for Candida albicans. The reason for this was a decline in the number of macrophages with phagocytic capacity (percent of phagocytosis) and in the number of C. albicans phagocytized per cell (phagocytic efficiency). The conclusion is that a short, acute exposure to a smoke-filled atmosphere induced a decrease in the phagocytic function of alveolar macrophages.