The importance of temporary layoffs in measured unemployment has not been solidly established empirically. Clark and Summers (1 979) maintain that these separations account for only a small fraction of U.S. unemployment. Administrative data analyzed in this paper show that temporay layoffs are an important feature of the Canadian labor market. Approximately 35 per cent of the variation in the Canadian unemployment rate over time can be accounted for by changes in temporary layoffs and about 45 per cent by variations in all temporary employment separations.