A radio labelling of a connected graph G is an one-to-one mapping f: V(G)→N such that d(u,w) +|f(u)-f(w)|≥1 + diam(G)∀ u,w∈V(G). The radio number of f denoted rn(f), is the maximum number assigned to any vertex of G. The radio number of G, denoted rn(G), is the minimum value of rn(f) taken over all labelings fof G. In this paper we have defined and completely determined the radio number of certain graphs with extended wheels namelyWW(r), SW(r),KDW(r) and HW(r).