Banks can differ markedly in their sources of income. Some focus on business lending, some on household lending, and some on fee-earning activities. Increasingly, however, most banks are diversifying into fee-earning activities. Such diversification is either justified (by the bank) or welcomed (by commentators), or both, as reducing the banks exposure to risk. Diversification across various sources of earnings is welcomed for, it is claimed, diversification reduces risk. Whether it does of course depends on how independent of each other the various earnings sources are. Traditionally fee income has been very stable; but, also traditionally, it has been a small part of the earnings stream of most banks. Has non-interest income remained stable, or at least uncorrelated with interest income, as banks have increased its importance in their earnings? This paper examines the variability of interest and non-interest income, and their correlation, for the banking systems of EU countries for the years 1994-98. It is found that the increased importance of non-interest income did, for most but not all categories of bank, stabilise profits in the European banking industry in those years. It is not, however, invariably more stable than interest income.