This paper aims to characterize, from a multidisciplinary perspective, the estimation of a supply function for milk cap (Lactarius deliciosus Gray L. ex Fr.), in Spain. The milk cap is a mushroom of great commercial relevance in Spain. The main objective of this work is to present empirical evidence in order to quantify both the effects of economic variables and mycological variables, in local markets. The paper starts, with an analysis of the main mechanisms that characterize wild mushrooms behavior. In the analysis of these markets, the relevance and structure of mushroom foreign trade in the European Union is also considered. Data availability is a fundamental point in the study of mushroom markets and determines, in most of works, research in the different stages of the value chain. In this work, the supply chain is estimated, with aggregated data, for the final stages of this vale chain, in a Central Market. The estimated supply function indicates an intense negative relationship between the temperature and the supply quantity. The rain elasticity at the mean is negative, and higher than the price elasticity at the mean. So, meteorological variables present an impact on the supplied quantity, which is even higher than price.