The article presents research on the loyalty of the nobility of Podlasie in the context of their attitude to tax liabilities to the state. The tax inventory for Podlasie from 1570 and the register of oaths for allegiance to Zygmunt August from 1569 were analysed. Comparison of these documents, using the prosopo-graphic and statistical methods, made it possible to estimate the number of representatives who did not pay taxes and took an oath, and to provide apre-liminary explanation of the determinants of this insubordination.