Abstract Background: Finding accurate health-related information on the Internet may be a real challenge for users lacking the critical skills necessary to assess the validity of online content, even if they browse websites that are compliant with credibility criteria. The aim of the study was to check whether an overall high website credibility or compliance to any of the individual criteria for credibility are correlated/associated with a higher quality of health-related information on a sample of Romanian and Hungarian stroke-related websites. Methods: The cross-sectional study included a sample of 50 websites presenting stroke for the general population in Romanian and Hungarian language. The websites’ compliance with 12 widely recognized credibility criteria, and the completeness and accuracy of the stroke-related articles found on the respective sites were systematically assessed by two independent evaluators applying a common evaluation procedure. Results: The mean value of the credibility score was 4.3 points (95% CI: 3.9–4.8), the mean value of the completeness score was 4.8 points (95% CI: 4.2–5.5), and the mean value of the accuracy score was 6.6 points (95% CI: 6.3–6.8). Correlation coefficients between the credibility score and completeness/accuracy score did not reach statistical significance (Spearman rho = 0.038, p = 0.793 and Spearman rho = 0.156, p = 0.278, respectively). With a few exceptions, the t-tests for independent sample comparison have shown no significant differences between websites that complied and those that did not comply with each individual credibility criterion. Conclusions: The mean credibility score of the Romanian and Hungarian stroke-related websites was poor and it was not correlated with neither completeness nor accuracy of the information displayed on the respective pages. With a few, practically irrelevant exceptions, compliance with individual credibility criteria was not associated with higher content quality on the investigated sample.