Blood samples were collected from 488 people living in an industrial and an agricultural area of Tarragona Province, Spain. The samples were subjected to blood lead analyses by atomic absorption spectrophotometry. Although in the industrial area men had higher blood lead levels than women, this difference was not statistically significant. Blood lead concentrations were related to a range of factors such as age, smoking and drinking habits. Both smoking and drinking habits were associated with a dose-dependent increase in blood lead levels, especially in men. On the other hand, delta-aminolevulinic acid dehydratase (ALA-D, EC 4.2.1.24) activity was determined in blood from 186 people of Tarragona Province. The results obtained were within the normal limit values (NLV) as defined by the WHO. The present data concerning Tarragona Province show that in relation to environmental health there is not a serious problem from lead contamination.