In response to the rising concerns about the rate of heroin-related fatalities, overdose prevention campaigns, run by both users' organizations and government agencies, have been implemented in a number of states across Australia. In Western Australia (WA) in mid-1997, various overdose prevention initiatives were implemented. These included the implementation of a protocol limiting police presence at overdose events; the commencement of naloxone administration by ambulance staff; and the establishment of the Opiate Overdose Prevention Strategy (OOPS) which provided follow-up for individuals treated for overdose in emergency departments. This paper reports the results of a multiple linear regression analysis of 60 months of time-series data, both prior to and following the implementation of these interventions, to determine their impact on the number of fatal heroin overdoses in WA. The model employed in the analysis controlled for changes over time in proxy indicators of use and community concerns about heroin, as well as market indicators. The results suggest that, although the interventions implemented have managed to reduce the expected number of fatalities, they have become less successful in doing so as time passes. This has implications for both existing and potential interventions to reduce fatal heroin-related overdose.