  Electroweak precision measurements, encoded in the oblique parameters, give
strong constraints on physics beyond the Standard Model. The oblique parameters
S, T, U (V, W, X) are calculated in the next-to-minimal supersymmetric model
(NMSSM). We outline the calculation of the oblique parameters in terms of
one-loop gauge-boson selfenergies and find sensitive restrictions for the NMSSM
parameter space.
