I show empirically that commuting time affects job acceptance, suggesting large indirect costs of traffic congestion. To quantify congestion's effect on the labor market, I build a model of frictional job search within a metropolitan area. Workers evaluate job offers based on productivity and commuting costs, taking congestion as given, but by accepting and commuting to distant jobs, affect others' labor market outcomes. Equilibrium employment transitions and wages are tightly linked to congestion. Calibrating the model to the London area, the congestion externality significantly decreases welfare and increases wage inequality. I show that the stronger are search frictions, the smaller are the welfare gains from a congestion tax. (JEL E24, J32, J62, R13, R41)