Global electroweak fits and gauge coupling unification

In this Letter we investigate if the rather poor Standard Model (SM) fit to all electroweak data can be improved in minimal supersymmetric extensions of the SM (MSSM) and if gauge coupling constant unification is still feasible in the MSSM, given the high precision of the measured gauge coupling constants. The results are: the probability of the electroweak fit does not improve significantly with supersymmetry and exact gauge unification is possible with the present coupling constants. (C) 2004 Elsevier B.V. All rights reserved.