By use of density functional theory and nonequilibrium Green’s function technique we have studied the electronic structure and transport properties of tubular Janus structures composed of hybridized carbon (C) and boron-nitride (BN) nanotubes (NTs) with carbon caps at both ends. The effect of chirality was probed by focusing on (5, 5) armchair and (9, 0) zigzag structures, both of which have similar radii and are metallic in the infinite length limit. The study has revealed a number of interesting properties: (1) The highest-occupied molecular orbital (HOMO)–lowest-unoccupied molecular orbtial (LUMO) gap is decreased when BN patch is inserted to zigzag structure but increased when it is inserted in the arm chair structure and graphene sheet. (2) The zigzag edges of the heterojunctions lead to anisotropy of frontier orbital distribution where the HOMO and LUMO are respectively predominated by B–C and N–C bonding states. Consequently, one side or one end becomes more reactive than the other. (3) The current in tubular Janus structures is reduced from that in pristine carbon nanotubes. At low bias, the current in the zigzag structure increases with increasing tube length while reverse is the case with the arm chair structure.