With the population ageing, the number of seniors with cognitive impairments is growing, as is the number of requests for competency assessments. The Competency Assessment Tool (CAT) was designed to assist health and social service professionals to clinically assess competency. A qualitative study was held to validate de CAT. Five focus group (including elders, caregivers and professionals from organizations protecting elders’ rights) were held, along with ten telephone interviews (with legal practitioners). All participants were asked for their overall opinion of the CAT and its relevance in improving assessments and protecting people’s rights. According to the results, the CAT is an innovative, comprehensive and relevant tool that provides a fair and nuanced assessment of competency. Implementing this tool will help to protect the rights and freedoms of the individuals evaluated by producing an assessment that will make it easier to identify the most appropriate protective measures.