This paper analyses in depth the causes of the Mexican peso crisis, so as to learn relevant lessons for similar crisis occurring in other developing or transitional economies. The study follows a relatively chronological order, examining first the apparently golden period, when Mexico was acclaimed world-wide as a successful reformer. The next section analyses the period when 'clouds emerge and darken', examining policy options that could have been followed by the economic authorities. The last section focuses on the devaluation of 20 December 1994, and the resulting crisis. In the analysis of the causes of the grave Mexican peso crisis, consensus is emerging around some of them. These include the large scale of the current account deficit,...