User interface evaluation has become important in developing usable health care technologies. Although usability engineering methods have been applied in the design and evaluation of health care software, available heuristics focus on task-work aspects and do not address stigma associated with many health conditions. We used a previous set of heuristics and propose a new set of anti-stigma heuristics to evaluate stigmatization in health care websites. The extended set of heuristics were concurrently applied in a heuristic evaluation and a cognitive walkthrough to evaluate an endometriosis and sexual pain website. The walkthrough involved 5 tasks that required 21 actions to execute. Twenty-six usability problems were identified and recommendations for re-design were made to the design team before end-user testing. The anti-stigma heuristics received worse ratings than the traditional heuristics, resulting in several design changes that might otherwise have been missed. Thus, the new anti-stigma heuristics were a valuable contribution.