This paper tests the economic importance of income uncertainty in the context of a measured factor arbitrage pricing theory model. This provides a test of the importance of uncertainty using a different methodology and data set than are traditionally used. If income uncertainty affects the investment climate, a statistically significant risk premium will be associated with assets that are affected by uncertainty. The empirical work in this essay finds that a generalized autoregressive conditional heteroskedasticity measure of income uncertainty is a priced factor in a model of the arbitrage pricing theory. The risk premium between a baa-rated 10-year corporate bond and a 10-year government bond, as well as the term structure, also are priced factors.