Research conducted in many research centers all over the world indicate health threats resulting from the presence of lead in the blood gradually decreases to the permissible amount. Lead accumulation in a living organism results in adverse changes in different body systems, symptoms of which include various behavioral changes. They can be reflected in grades obtained by the child at school. The aim of this paper was to establish whether the blood lead level diversify the boys in the respect of their school performance during consecutive years of primary education. The amount of lead in blood of 94 boys at the age of 10 has been measured; subsequently, the group of subjects was divided into two subgroups; the first one (termed in this paper „L”) comprised students whose Pb-B level was lower than 6 μg/dl (4,846 μg/dl on average) and the second one (termed „H”) comprised boys whose blood level exceeded 6 μg/dl (9,256 μg/dl on average). Academic performance in the arts, scientific subjects, geography and natural science in respective groups was assessed. Said procedure was replicated in respective subgroups after a year when the subjects were 11 years old. It was ascertained that the academic performance of the boys with higher blood lead levels deteriorated in scientific subjects and tended to worsen also in other school subject groups. Performance of the students whose blood lead level was lower in the initial examination remained unchanged or improved.