Resumo. The incidence of the fungus Cylindrocladium candelabrum, causal agent of diseases in eucalyptus cultivation in Brazil increased significantly, demanding the use fungicides for its controlled. However, pesticides cause environmental contamination and damage to the health of living organisms. Thus, the present study evaluated the in vitro inhibitory effect of the extracts of Cinnamomum zeylanicum on mycelial growth of Cylindrocladium candelabrum. The extracts were obtained by percolation with the solvents hexano (EBH), ethyl acetate (EBAcoEt) or methanol (EBM). The phytochemical analyses were based on the conditions established in the Manual for Phytochemical and Chromatographic Analysis of Plant Extract. In order to evaluate the effect of the extracts on mycelial growth inhibition, the following treatments were used: control, consisting of culture medium with no extracts (negative control); concentrations of 5, 10 or 20 mg mL-1 of the crude extracts of cinnamon; and 5 mL of Chlorothalonil fungicide (positive control), all incorporated into the PDA (Potato-Destrose-Agar) culture medium. The results of the phytochemical study identified reducing sugars, phenols, tannins, steroids, triterpenoids, and alkaloids for EBH and EBAcoEt extracts. EBM extract differentiated by the presence of anthraquinones, foamy saponins and flavonoids. The crude extracts of Cinnamomum zeylanicum presented significant differences in relation to the control treatments. The greater the concentration of crude extract, the greater the antifungal activity in the phytopathogen, and the treatment with EBM was more effective in inhibiting mycelial growth of the phytopathogen. Therefore, the inhibitory action of Cinnamomum zeylanicum crude extracts on the mycelial growth of Cylindrocladium candelabrum was demonstrated; however, further studies must be done, such as in vivo tests, to better understand the efficacy of these extracts.