There are three astronomical observatories in Mexico working on research programs. The oldest one is located at Tonantzintla, Puebla; the largest is at San Pedro Martir, Baja California; and the youngest, not yet in full operation, at Cananea, Sonora. The one at Tonantzintla suffers, by far, the largest light pollution problems; that at San Pedro Martir has the darkest skies but is relatively close to regions of potential touristic and mining developments. In this paper we summarize the existing and potential polluting problems arising from manmade light sources near those observatories, and suggest some possible steps to be taken in order to minimize their adverse effects on astronomical observations.