Interventions that may reduce the number and severity of potentially harmful post-stroke complications are desirable. This study explored whether very early and frequent mobilisation (VEM) affected complication type (immobility/stroke related), number and severity.Secondary analysis from phase II, randomised controlled trial. Patients admitted within 24 h of stroke, whose physiological parameters fell within set limits, were randomised to either VEM, commencing <24 h, or standard care. Complications to 3 months were recorded by a blinded assessor and classified by a neurologist. Analysis was intention to treat.Seventy-one patients were recruited (standard care 33; VEM 38).There were no significant group differences in the number, type or severity of complications by 3 months, and most patients (81.6%) experienced one or more complications. Falls were common, while depression was absent. The multivariate analysis showed older age (OR 1.10, 95% CI: 1.02-1.18, p = 0.009) and longer length of stay (OR 1.18, 95% CI: 1.06-1.32, p = 0.002) were associated with experiencing an immobility-related complication.Interventions that promote recovery and reduce complications may consequently reduce length of stay. The larger phase III trial currently underway may shed light on whether increasing mobilisation reduces complications after stroke.