Liquid smoke and heat treatments were evaluated for their potential use to inhibit growth of Aspergillus oryzae, Penicillium camemberti, and Penicillium roqueforti on Cheddar cheese. A. oryzae had a longer lag period and P. roqueforti grew faster radially on cheese heated at 42°C for 1 h than on unheated cheese. Mold growth on cheese heated at 24 and 33°C for 1 h was not significantly different from that on the unheated control. Liquid smoke applied to the surface of cheese totally inhibited growth of A. oryzae and significantly increased the lag period of P. camemberti and P. roqueforti. Of eight major phenolic compounds in smoke, only isoeugenol inhibited all three molds. P. camemberti was slightly inhibited by m-cresol and p-cresol, while A. oryzae was inhibited by guaiacol, 4-methylguaiacol, m-cresol, and p-cresol. Results of this study showed that phenolic compounds found in smoke are primarily responsible for inhibition of molds on smoked Cheddar cheese.