In the years 1995–1996 a field experiment in the Experiments Station in Wierzchucinek belonging to the Technical-Agriculture University was carried out. The effect of spraying fertilization with molybdenum and boron on the content of oat grain and its fractional composition was tested. Molybdenum and boron were applied as single inorganic salts. The experiment was established as one treatment on gray podsolic soil, where the content assimilable forms of phosphorus, potassium, molybdenum and boron were average. No effect under tested microelements on the increase of protein in the grain was found. The effect of the tested microelements on the increase of the albumins and prolamins content and decrease of the content of glutelins in the protein of the oat grain was statisticaly confirmed. As the result of applied fertilization the sum of alubimins and globulins increased as well, but the sum of gliutelins and prolamines decreased.