Introduction: The largest outbreak of human and animal sporotrichosis is seen in Rio de Janeiro, Brazil, due to zoonotic transmission of Sporothrix spp. from sick cats, emphasizing the importance of this disease as a public health problem. The treatment of cats remains a challenge, especially when mucosal lesions are present. Methods: The efficacy of ITZ and ITZ+KI in feline sporotrichosis with mucosal involvement was compared in a randomized controlled clinical trial at INI/ Fiocruz from 2013 to 2016. Fifty-nine naïve cats with sporotrichosis mycologically confirmed were included into the groups G1: ITZ (n=32) and G2: ITZ+KI (n=27). Cats from both groups received capsule of ITZ 100mg/day and cats from G2 also received KI 2.5mg-20mg/Kg/day. Clinical assessment was performed at each 30 days. Data were recorded in Epidata and analyzed using R software. Results: All cats presented both skin and mucosal lesions. Cure rate was 25% (n=8) in G1 and 88.8% (n=24) in G2. The median time of treatment was 19.5 weeks for G1 and 22 weeks for G2. Clinical adverse effects did not differ among groups; 43% (G1) vs 44% (G2). Conclusion: The association of ITZ and KI is markedly superior to ITZ monotherapy in naïve cats with sporotrichosis presenting mucosal lesions.