Search for supersymmetric neutral Higgs h in the decay -> mumu in ATLAS detector.

Results are presented on the possibility of MSSM h discovery in region of high tan beta,larger than 15, and mass close to 100 GeV in the channel h --> mumu, accompanied by two b-jets. This region not completly covered from neither LEP neither Tevatron data constitutes a potential test for the MSSM Higgs discovery. In this note a use of a pure experimental background technique, with different approach from a previous one [ATL-Phy-2002-021], to subtract the most copious background of Z --> mumu is proposed with promising results.