Abstract. We address the problem of studying the boundedness, compactness and weak compactness of the integral operators Tg(f )(z) = z 0 f (ζ)g ′ (ζ) dζ acting from a Banach space X into H ∞ . We obtain a collection of general results which are appropriately applied and mixed with specific techniques in order to solve the posed questions to particular choices of X.