This article examines the uncertainty of household income in European Union countries and in one accession country - Poland. Using the data from the Household Budget Surveys for a panel of twelve European Union countries in years 1995-98, and the Household Budget Survey for the Polish households' panel for 1997-2000, we estimate the uncertainty of household income by decomposing it into a variance of permanent income and a variance of transitory income. For particular countries we assess these two measures of income uncertainty using different criteria: age, gender, main economic activity, education and professional status of the household head.