  In this work we investigate the consequences of the Jaffe and Wilczek diquark
model in the framework of QCD sum rules. An analysis of the Theta^+(1540) as
(ud)^2\bar{s} state shows that the mass of the pentaquark is compatible with
the experimentally measured value. The mass difference between the Theta^+ and
the pentaquark with the quantum numbers of the nucleon amounts to 70 MeV and is
consistent with the interpretation of the N(1440) as a pentaquark.
