  We derive a general expression for Delta rho (or, equivalently, for the
oblique parameter T) in the SU(2) x U(1) electroweak model with an arbitrary
number of scalar SU(2) doublets, with hypercharge +-1/2, and an arbitrary
number of scalar SU(2) singlets. The experimental bound on Delta rho
constitutes a strong constraint on the masses and mixings of the scalar
particles in that model.
