This paper examines the evolution over the past few decades in inequality in working hours. We use data for the US, the UK, France and Germany to examine hours dispersion and assess their contribution to rising earnings inequality. We find that hours inequality is an important force in the increase in inequality, other than in the US. In particular, the elasticity of hours with respect to wages used to be negative, thus creating an equalizing force as those with lower hourly wages worked longer hours. This elasticity has increased over time, becoming null or positive, hence eroding an important equalizing force.