X0201 42003-11-04 0000706539 CHIRON CORP CHIR 0001198332 PENHOET EDWARD 4560 HORTON STREET EMERYVILLE CA 94608 1000Common Stock2003-11-044M0500022.7188A213296DCommon Stock2003-11-044S0500053.989D208296DCommon Stock2003-11-044M06500021.6563A273296DCommon Stock2003-11-044S06500053.89D208296DCommon Stock2003-11-044M01000021.6563A218296DCommon Stock2003-11-044S01000053.989D208296DEmployee Stock Option (Right to Buy)22.71882003-11-044M05000D2000-02-182009-02-18Common Stock50000DEmployee Stock Option (Right to Buy)21.65632003-11-044M075000D1999-11-132009-05-13Common Stock750000DThis amount includes 294 share rights which are subject to certain vesting.Stock Option granted under the Chiron 1991 Stock Option Plan in transaction exempt under Rule 16b-3.Right to exercise vests as to ?? of the total shares on the first anniversary of the grant date and monthly thereafter as to 1/48 of total shares. The Chiron 1991 Stock Option Plan has provisions permitting, in the discretion of the Administrator, the withholding of shares from the grant to satisfy income tax withholding. The option vests 100% upon Reporting Person's retirement from Chiron. Option is exercisable for up to 5 years after Reporting Person retires from Chiron.Option vested 100% six months from grant date, which was November 13, 1999. Option is exercisable for up to 3 years after Reporting Person's last date of employment or date of services as a director.Edward E. Penhoet by Naima Robinson as Atty-in-Fact2003-11-05