This article checks for the robustness of the estimate of the impact of market access (MA) on the regional variability of human capital, derived from the New Economic Geography literature. The hypothesis is that the estimate of the coefficient of the measure of MA is actually capturing the effect of regional differences in the industrial mix and the spatial dependence in the distribution of human capital. Results for the Spanish provinces indicate that the estimated impact of MA vanishes and becomes nonsignificant once these two elements are included in the empirical analysis.