Purpose This study was conducted to determine the effect of correct handwashing and mask-wearing training on COVID-19 fear and generalized anxiety in cardiac patients. Methods Randomized controlled experimental study with the formation of intervention and control groups. Design The study (triple-blind) was conducted between August 11 and November 17, 2020, in the cardiology clinic of a tertiary hospital in western Turkey. The pre-study sample size was calculated as a minimum 45 at 80% strength, 0.05 significance level, and 0.60 influence quantity for each group. 112 volunteers meeting the criteria were included in the study. The study was completed with a total of 105 individuals in the intervention group (n=50) and control group (n=53). The post-study strength was (1- beta) =1. This study was performed in five stages: (1) collection of data, (2) randomization, (3) providing training, (4) contacting the intervention and control groups for follow-up a month later, and (5) collection of the follow-up data. Findings The training provided to cardiac patients increased the correct handwashing technique (U=36.00; p<0.001) and the correct mask-wearing technique (U=99.00; p<0.001) and decreased COVID-19 fear (U=883.5; p<0.001) and anxiety (U=751.0; p<0.001) (p <.05). Conclusion It can be considered that the training provided to the cardiac patients in preventing COVID-19 may also be suitable for other risk groups. Clinical Evidence Practical training at the individual level can be used to train cardiac patients.