The article takes up the issue of sensitivity of public revenue originating from personal income tax (PIT) proceeds to fluctuations in macroeconomic prosperity. Short term elasticities in separate components of PIT were arrived at via the study of output fluctuations' impact on the tax assessment base. The results of the analysis suggest that short term elasticity of budgetary revenue from PIT is higher than one (during 1995-2003 it amounted, on the average, to 1.23). This implies that changes in PIT inflows are relatively greater than fluctuations in GDP. Higher short term elasticity in PIT revenues in relation to GDP also signifies that during expansion phase public finances should enjoy a marked increase in revenues derived from PIT collection.