BACKGROUND Knowing when to commence physical rehabilitation after stroke is important to ensure optimal benefit for stroke survivors and efficient health care. The aims of this review were to: determine the effects on mortality, function and complications when physical rehabilitation commences 'early' (within seven days of stroke); and describe the effects of early transfer to rehabilitation wards/hospitals when sustained rehabilitation is unavailable in acute stroke units. RESULTS From 3751 potential articles we included 5 randomized controlled trials and 38 cohort studies. Meta-analysis was performed with 3 randomized controlled trials involving 159 people to investigate the effects of commencing physical rehabilitation within 24 h of stroke compared to 48 h. Commencing physical rehabilitation within 24 h trended towards greater mortality (Mantel-Haenszel odds ratio 2.58; 95% confidence interval 0.98 to 6.79, P = 0.06), with no differences in complications or health outcomes. The cohort studies provided evidence of benefits when physical rehabilitation was commenced on the day of admission (n = 1), within 3 days of stroke (n = 3), or 'sooner rather than later' (3 of 4 studies). The effect of earlier transfer to rehabilitation was reported in 32 cohort studies. In 23/26 (88%) cohort studies that accounted for age and stroke severity, results favored earlier transfer for improving post-stroke function, with no consensus on timeframes. CONCLUSIONS In summary, the benefits of commencing physical rehabilitation within 24 h of stroke remain unclear from the current literature. Commencing physical rehabilitation or transferring to rehabilitation services 'early' may provide better functional outcomes.