Among the fungi that cause damage to the common bean and are disseminated by the seeds, Colletotrichum lindemuthianum (Sacc. e Magn.) Briosi e Cavara stands out. This fungus causes anthracnose in common bean ( Phaseolus vulgaris L.). Use of natural compounds is a viable and safer option than chemicals to manage this disease. Essential oils have shown antifungal potential against phytopathogenic fungi. According to the results of the in vitro test, we observed complete inhibition of the growth of C. lindemuthianum with the use of cassia cinnamon essential oil ( Cinnamomum cassia ) (EO) and its major component ( E )-Cinnamaldehyde, presenting MIC of 125 µg/mL, while the commercial fungicide presented MIC of 30.6 µg/mL. And in vivo , where seeds naturally infected with C. lindemuthianum were treated with the EO and the substance in a solution with commercial soybean oil, we observed that the treatments did not affect germination and initial seed vigor. In addition, the seed treatment with solutions formulated from EO and ( E )-cinnamaldehyde was efficient for reducing the incidence of anthracnose over the days evaluated, as well as for the commercial fungicide used (methyl thiophanate). This is the first study to demonstrate the efficacy of C. cassia oil and (E)-cinnamaldehyde in the control of C. lindemuthianum through the treatment of common bean seeds.