Critical areas of the E45 highway (Troncal Amazónica), Morona Santiago Province, Ecuador, have an alarming history of slope instability, which have blocked the road and negatively impacted the most vulnerable population due to unsafe conditions. In the present investigation, the stability of access slopes to the bridge over the Copueno River, Morona Santiago, Ecuador Province, is evaluated. The geological-geotechnical characterization, the processes that influence the detachment of materials, evaluation and analysis of the limit states of failure of the instability sites are reported. [ABSTRACT FROM AUTHOR]