X0201 42003-11-04 0000706539 CHIRON CORP CHIR 0001229444 LANCE SEAN P 4560 HORTON STREET EMERYVILLE CA 94608 1000Common Stock2003-11-044M0900021.0625A31149DCommon Stock2003-11-044S0900054.15D22149DEmployee Stock Option (Right to Buy)21.06252003-11-044M09000D1999-05-012008-03-18Common Stock9000732000DStock Option granted under the Chiron 1991 Stock Option Plan in transaction exempt under Rule 16b-3.125,000 shares vested on 05/01/99; 475,000 vested in 48 successive equal monthly installments beginning on the first annual anniversary of Reporting Person's employment; vesting of 75,000 shares was accelerated as of 05/17/01 because certain performance goals were attained; the remaining 75,000 shares vested as of 05/01/03.Sean P. Lance by Carolyn Mar-Andreotti as Atty-in-Fact2003-11-04