A reaction of C60 with an equimolar amount of chlorophenyldiazirine in refluxing toluene afforded the C60-chlorophenylcarbene 1:1 adduct in 37% yield. The adduct was shown to have the cyclopropane structure by C-13 NMR and exhibited reversible reduction waves at the potential about 0.1 V more negative and an irreversible oxidation peak at nearly the same potential as compared with those of C60 itself.