This paper examines the ethnic determinants of constituency delineations and voting patterns in West Malaysia over the past five general elections, paying particular attention to the ramifications of the 2002 re-delineation exercise. I show that the 2002 re-delineation exercise reduced markedly the ethnic bias of the electoral system yet increased the overall imbalance in constituency size. I then argue that the old electoral logic of small Malay-dominated rural constituencies, which tended to vote strongly for the Alliance/BN government (incumbent since independence), and large Chinese-dominated urban constituencies, which tended to vote more for the opposition, has become increasingly irrelevant thanks to Malay urbanization and shifting ethnic voting patterns. The paper thus concludes that the 2002 exercise represented the 'correction' of an increasing imbalance between the patterns of the government's electoral support and constituency delineations. Ethnic bias in the electoral system was substantially replaced by a direct political bias in favour of the BN government.