The magnetic response of electrons in a zigzag carbon nanotube (CN) threaded by an Aharonov Bohm flux φ is carefully analyzed by using a Hartree Fock approximation. The ground state energy as a function of the magnetic field, B, and the electron–electron repulsion strength, U, are obtained for Ne interacting electrons confined in short (∼100 nm) and long (∼1 μm) CNs. The spin and orbital magnetization responses to the magnetic field variations are discussed. The CN transport properties are investigated and periodic field dependent oscillations are predicted for both longitudinal ballistic and persistent currents. The behavior of persistent current is investigated as a function of U and a significant suppression in current amplitude is observed when the strength of the electron–electron repulsion increases.