The adsorption of N-2 on close-ended single-walled carbon nanotube bundles was studied at different temperatures ranging from 81 to 94 K. The isosteric heat of adsorption was obtained from the adsorption isotherm measurements, and the binding energy of N-2 was estimated from the isosteric heat of adsorption data in the low-coverage region. The estimated binding energy was about 86 meV, and this value lies between those of Ne and CH4 on nanotube bundles. It was also observed that the isosteric heat of adsorption increased in regions of low coverage and decreased as the coverage increased. T his was due to both interactions between N-2 molecules and the heterogeneity of the nanotube bundles.