The stability of molecular junctions is crucial for any application of molecular electronics. Degradation of molecular junctions when exposed to ambient conditions is regularly observed. In this report the stability of large-area molecular junctions under ambient conditions for more than two years is presented. Furthermore, the thermal stability of molecular junctions at elevated temperatures is investigated. A transition temperature at 50 degrees C was observed for molecular junctions based on self-assembled monolayers of alkanedithiols, above which the resistance decreases exponentially with temperature. This transition temperature limits the process window during fabrication and the temperature window during operation. (C) 2009 Elsevier B.V. All rights reserved.