Lead and cadmium was determined in whole blood samples obtained from 473 nonoccupationally exposed adult persons in Sweden in 1980. Analyses were performed using atomic absorption spectrophotometry equipped with an electrothermal atomization unit. Accuracy of the analysis was confirmed by the analysis of quality control samples. Blood lead concentrations were shown to be significantly influenced by sex, smoking habits, and alcohol consumption. Current male smokers had a median blood lead level of 92 micrograms Pb/liter, as compared to 77 micrograms Pb/liter for nonsmokers. For females the corresponding values were 69 micrograms Pb/liter and 57 micrograms Pb/liter for current smokers and nonsmokers, respectively. Highly significant correlations were found between stated alcohol consumption and blood lead in most of the different sex and smoking categories. People living in apartments close to streets with heavy traffic in Stockholm had slightly, but not significantly, higher blood lead levels when compared to people living in areas of this city with low traffic density. Blood cadmium levels were very strongly affected by smoking habits. A significant correlation existed between the number of cigarettes consumed daily and blood cadmium concentration. The median blood cadmium level for nonsmoking males was 0.2 micrograms Cd/liter (less than or equal to 0.2, detection limit) and for females 0.3 micrograms Cd/liter. About 90% of all nonsmokers had cadmium concentrations in blood below 0.6 micrograms Cd/liter, whereas about 90% of the current male and female smokers had cadmium concentrations in blood of 0.6 micrograms Cd/liter or more.