The visible photoluminescence (PL) from 0.44 nm carbon nanotubes in zeolite templates was investigated. A broad emission band with an efficiency of ∼1%-5% was exhibited by PL. Strong polarization dependence was also observed on excitation and emission, which indicated preferential optical dipole along axis of carbon nanotubes. The results show that (3, 3) and (4, 2) tubes were responsible for PL peaks at ∼2.6 and ∼1.7 eV.