Lim made her political debut in Marine Parade GRC at the
1997 general election as part of a six-member PAP team, which won in a walkover; she became the MP for the Serangoon division. In the
2001 general election, she remained in the GRC as part of a six-member team, experiencing a second walkover. From 1 April 2002 to 11 August 2004, she was the Deputy Speaker of Parliament and Chairperson of the Public Accounts Committee. Lim was appointed the Minister of State for Finance and Transport on 12 August 2004. At the
2006 general election, after her Serangoon division was shifted to Aljunied GRC, Lim contested in said GRC as part of a five-member PAP team; they defeated the
Workers' Party (WP) with 56.09% of the vote. She was promoted to Senior Minister of State for Finance and Transport on 1 April 2008. On 1 April 2009, Lim become the first woman to serve in Singapore's Cabinet when she was made a Minister in the Prime Minister's Office, Second Minister for Finance and Second Minister for Transport. Between 2002 and 2011, Lim was a member of the Central Executive Committee of the PAP, and the Chairman of the party's Women's Wing. She was inducted into the Singapore Council of Women's Organisation (SCWO) Hall of Fame on 31 March 2010, and she received the
Her World Woman of the Year Award on 23 April 2010. In the
2011 general election, Lim led the PAP team for Aljunied GRC alongside fellow minister
George Yeo, but lost to the WP with 45.28% of the vote. She subsequently stepped down from the
Central Executive Committee (CEC) of the PAP and announced her retirement from politics, saying she was surprised by the depth of resentment felt by citizens towards the government. ==Post-political career==