Irradiation of polymer-based gecko-like synthetic adhesives (GSAs) using an accelerated beam of He++ ions has been performed. This irradiation simulates large radiation doses that the GSAs may experience if deployed on a robotic platform in some radiological environments. After irradiation, the adhesive samples were tested for adhesion on a three-axis adhesion testing stage and were examined via scanning electron microscope. The GSA samples showed significant changes in surface morphology at high radiation doses. Additionally, radiation doses larger than 750 kGy resulted in a significant deterioration of the adhesive performance. Eventually, the adhesive samples lost all ability to generate frictional adhesion. Such results allow us to make quantitative statements about the applicability of GSAs for robotic applications in nuclear environments.