Abstract. The problem is to show that (1) V (t, x) = S(t,t 0 H (t, s, x(s)) ds) has a solution, where V defines a contraction,Ṽ , and S defines a compact map,S. A fixed point of P ϕ =Sϕ + (I −Ṽ )ϕ would solve the problem. Such equations arise naturally in the search for a solution of f (t, x) = 0 where f(0, 0) = 0, but ∂f(0, 0)/∂x = 0 so that the standard conditions of the implicit function theorem fail. Now P ϕ =Sϕ + (I −Ṽ )ϕ would be in the form for a classical fixed point theorem of Krasnoselskii if I −Ṽ were a contraction. But I −Ṽ fails to be a contraction for precisely the same reasons that the implicit function theorem fails. We verify that I −Ṽ has enough properties that an extension of Krasnoselskii's theorem still holds and, hence, (1) has a solution. This substantially improves the classical implicit function theorem and proves that a general class of integral equations has a solution.