Results indicated that thefts of new cars in Australia have decreased since July 2001, when all new passenger vehicles sold in the country were required to have standard engine immobilizers prior to sale. While the theft of new cars has decline, there is evidence that the theft of vehicles in Australia has shifted to older models, not fitted with engine immobilizers. The study and findings replicated a study undertaken in the United Kingdom by Brown and Thomas (1998), which also discovered that immobilizers were effective in reducing vehicle theft rates. The authors conclude that while engine immobilizers are effective at protecting newer vehicles from theft, other strategies need to be employed to protect older model vehicles, strategies such as all-over vehicle marking systems and public awareness campaigns. The data also pointed toward a shift to the theft of older vehicles lacking the engine immobilizers. Data on vehicle thefts in Australia were drawn from the National Comprehensive Auto-theft Research System (CARS) Project containing police data on all motor vehicle thefts and vehicle registration data from all Australian States and Territories. The analysis compared 2 calendar years--2000 (before immobilization implementation) and 2004 (after immobilization implementation)--in terms of theft rates. Descriptive statistics were used to analyze the data. Tables, figures, footnotes, references