In this paper we provide the first estimate of the intertemporal substitution for leisure in Spain, accounting for the impact of human capital accumulation. This would allow uncovering whether the intertemporal labour supply of Spanish workers is affected by human capital. Our empirical strategy consists of estimating the equation for the intertemporal substitution of leisure with and without accounting for human capital, what allows to detect hypothetical estimation biases associated to omitting the impact of human capital. To that end, we build a pseudo-panel data set combining the Spanish Family Expenditure Survey and the Labour Survey over the period 1987–1997. While the model that ignores human capital accumulation provides an estimate of the intertemporal elasticity of substitution for leisure about 0.25, comparable to previously available estimates for Spain and other economies, the model with human capital provides an estimate about 0.5, what confirms the existence of a bias in the former estimates. Finally, this bias is larger for the younger cohorts than for the older ones.