Properties of the excited states of C-60 incorporated into a cationic homooxacalix[3]arene (C-60/calixarene) in water have been investigated and compared with bare C-60 in benzene. A new transient absorption band which appeared at about 545 nm was attributed to triplet-triplet (T-T) absorption band of C-60/calixarene. The lambda(max) Of the T-T transition shifts to the shorter wavelength compared with that of bare C-60 in benzene and the decay rate increases very much.