Percutaneous coronary intervention (PCI) appears to be superior to in-hospital fibrinolysis for most patients with ST-elevation myocardial infarction (STEMI). However, few hospitals have PCI capability. The optimal prehospital strategy for facilitating rapid coronary reperfusion in STEMI patients is unclear. We sought to determine whether direct transport of adult STEMI patients by emergency medical services to primary PCI centres improves 30-day all-cause mortality when compared with a strategy of transportation to the closest hospital. We systematically searched MEDLINE, EMBASE, Cochrane "CENTRAL" database (1980-July 2007) and several other electronic databases. Two authors independently as sessed citations for relevance. Two authors independently abstracted data from included studies. We included studies that, 1) transported patients directly to a PCI-capable centre for primary PCI, 2) had a control group that was transported to the closest hospital and 3) reported outcomes of treatment time intervals, all-cause mortality, reinfarction rate, stroke rate or the frequency of cardiogenic shock. We used a random effects model to provide pooled estimates of relative risk (RR) when data allowed. We identified 2264 citations with the search. Five studies, including 980 STEMI patients, met inclusion criteria, and were clinically heterogeneous and of variable quality. Most studies were European (3/5) and involved physician out-of-hospital care providers. There was a trend toward increased survival with direct transport to primary PCI but this was not statistically significant (RR 0.51, 95% confidence interval [CI] 0.24-1.10). One study reported nonsignificant reductions in reinfarction (RR 0.43, 95% CI 0.11-1.60) and stroke (RR 0.33, 95% CI 0.01-8.06) with direct transport for primary PCI. There is insufficient evidence to support the effectiveness of direct transport of patients with STEMI for primary PCI when compared with transportation to the closest hospital.