Previous research has shown that there are a variety of eHealth usability evaluation methods suitable for agile, easily applicable, and useful eHealth usability evaluations. However, it is unclear whether such eHealth usability evaluation methods are also applicable with elderly users. This study aims to examine the challenges in applying eHealth usability evaluation methods with elderly users and how these challenges can be overcome. We chose three established eHealth usability evaluation methods to evaluate an eHealth intervention: (1) Co-Discovery Evaluation, (2) Cooperative Usability Testing, and (3) Remote User Testing combined with Think Aloud. The case study was conducted with seven Austrian elderly users. We supplemented the case study (March, 2021) with a systematic review (March, 2022) to identify (1) applied eHealth usability evaluation methods to elderly and (2) challenges of eHealth usability evaluations with elderly. Our results showed that Remote User Testing combined with Think Aloud could successfully be applied to evaluate the eHealth intervention with elderly users. However, Cooperative Usability Testing and Co-Discovery Evaluation were not suitable. The results of the systematic review showed that user-based eHealth usability evaluation methods are mostly applied to conduct eHealth usability evaluations with elderly users. Overall, the results showed that not all established eHealth usability evaluation methods are applicable with elderly users. Based on the case study and the systematic review, we developed 24 recommendations on how to deal with challenges during eHealth usability evaluations. The recommendations contribute to improving the accessibility, acceptability, and usability of eHealth interventions by the elderly.