. Math. 25B(4) (2004) [545][546][547][548][549][550][551][552][553][554] classified all arctransitive cubic graphs of order 4p with p a prime. In this paper, we shall generalize this result by classifying all connected arc-transitive cubic graphs of order four times an odd square-free integer. It is shown that, for each of such graphs Γ, either the full automorphism group Aut Γ is isomorphic to PSL(2, p), PGL(2, p), PSL(2, p) × Z 2 or PGL(2, p) × Z 2 , or Γ is isomorphic to one of 5 graphs.