OBJECTIVES: The increase in PBS expenditure over the past two decades led to the Australian Government implementing several cost containment measures. The objective of the present study was to investigate the impact of these reforms on PBS prescribing volumes and expenditure. METHODS: Data retrieved from Medicare Australia’s PBS Statistics database provided monthly government expenditure (benefit) and prescription volume (service) data. Segmented linear regression models were used to analyse the time series data starting from 1 January 1992 to 31 March 2012. In each segment, between implementing the cost containment measures, two parameters, the level and trend were used to estimate the impact of the intervention. A lag of 12 months was applied to adjust for seasonality and forward stepwise eliminations were applied to obtain a parsimonious model. Seven cost containment measures were investigated: the economic evaluation requirement for drug listing (1/01/1993­), re-supply limits (1/11/1994), two co-payment increases (1/01/1997 & 1/01/2005), therapeutic group premium (TGP) policy (1/02/1998), safety net 20-day rule (1/01/2006), and price reductions in multiple brand drugs in Formulary 2 (F2) (1/08/2008). RESULTS: All interventions except the re-supply limits policy were found to have a significant impact on PBS services or benefits. Reductions in the services and benefits trend were observed in two measures, the TGP policy and safety net 20-day rule while a reduction in the services trend was observed for the economic evaluation requirement measure. No significant trend changes were observed in the post F2 price reductions while higher co-payments resulted in a reduction in the level of services followed by an increase in the trend of services and benefits. CONCLUSIONS: Many of the cost containment measures implemented in Australia have been effective in containing cost. Among these measures, the safety net 20-days rule was estimated to be the most effective in reducing drugs utilisation and expenditure.