Some new criteria for the oscillation of all solutions of third order nonlinear difference equations of the form Delta(a(n)(Delta(2)x(n))(alpha)) + q(n)f(x[g(n)]) = 0 and Delta(a(n)(Delta(2)x(n))(alpha)) = q(n)f(x[g(n)]) + p(n)h(x[sigma(n)]) with Sigma(infinity) a(-1/alpha) (n) < infinity are established.