An update of the searches for charginos and gravitinos is presented, based
on a data sample corresponding to the 158 pb(-1) recorded by the DELPHI det
ector in 1998, at a centre-of-mass energy of 189 GeV. No evidence for a sig
nal was found. The lower mass limits are 4-5 GeV/c(2) higher than those obt
ained at a centre-of-mass energy of 183 GeV. The (mu, M-2) MSSM domain excl
uded by combining the chargino searches with neutralino searches at the Z r
esonance implies a limit on the mass of the lightest neutralino which, for
a heavy sneutrino, is constrained to be above 31.0 GeV/c(2) for tan beta gr
eater than or equal to 1. (C) 2000 Elsevier Science B.V. All rights reserve
d.