The data taken with ANTARES from 2007 to 2010 with a total lifetime of 863 days have been analysed in view of a possible neutrino oscillation signal. The flux of vertical upward going muon neutrinos should be completely suppressed at energies of 24 GeV due to neutrino oscillations. A dedicated algorithm is used, which allows the reliable reconstruction of muon tracks with energies as low as 20 GeV. The oscillation signal is extracted by comparing two event samples: a low energy sample of vertical upward going tracks seen on a single detector line and a higher energetic set of more isotropic events seen on several detector lines. First results of the measurements of the oscillation parameters are given.