We performed the ultraviolet photoemission spectroscopy study of single-walled carbon nanotubes (SWCNTs) encapsulating C59N. The work function of the C59N@SWCNT is estimated to be larger than that of the SWCNT. The pi states of the SWCNT shift toward the Fermi level upon encapsulation of C59N. The C59N pea spectrum is roughly similar to that of the (C59N)(2), but some peaks shift. The results suggest a small charge transfer from the SWCNT to the C59N pea, which is in contrast to the previously reported n-type FET characteristics. This discrepancy is probably due to the difference in the molecular form of C59N. (C) 2013 Elsevier B.V. All rights reserved.