Aim To investigate knowledge levels concerning COVID-19 in elderly patients with T2DM. Methods This cross-sectional, quantitative, observational, and descriptive study was undertaken among elderly individuals with T2DM involved in a body balance rehabilitation program that had been suspended due to social isolation. The study participants comprised elderly individuals with T2DM, contactable using fixed or mobile telephones. Data concerning participants’ socioeconomic variables and knowledge of COVID-19 were collated, using a Brazil Ministry of Health guidelines checklist. Mann–Whitney and Spearman’s correlation tests were used to analyze their responses. Results Of 30 elderly participants, 76.7% were women and 63.3% were married. The average age was 69.96 ± 4.46 years. The most cited information medium was television (96.6%). Of a possible 24 correct responses on the checklist, the median correct response score was 7.5. No significant relationship was observed between the total checklist score and the variables studied. Conclusion Elderly participants did not have in-depth knowledge concerning COVID-19, which suggests that their knowledge sources may be deficient or that their capacity to retain information was inadequate.