The aim of the study was to compare the efficacy of balance training in a balance trainer, a newly developed mechanical device for training balance, with conventional balance training in subacute stroke patients. This was a randomized controlled study. Fifty participants met the inclusion criteria and 39 finished the study. The participants were randomly divided into control and balance trainer groups. The first had conventional balance training while the second trained balance in the balance trainer. All the participants trained balance 20 min per day, 5 days per week for 4 weeks and had additional 25 min of physiotherapy. Balance was assessed by the Berg Balance Scale, one-leg standing, Timed Up and Go (TUG) Test and 10 m walk. There was significant improvement in Berg Balance Scale (P less than 0.001), TUG (P less than 0.001) and 10 m walk (P=0.001) in both the groups, whereas no differences were found in any of these measures between the two groups either regarding overall average level or regarding average improvement. Both the groups improved significantly in standing on the healthy (P=0.001) as well as the impaired lower limb (P=0.005), whereby no significant differences were observed between the groups. Within both groups, significantly fewer subjects needed assistance of a physiotherapist for the 10 m walk and the TUG test at the end than at the beginning of the study (P=0.016). It can be concluded that both conventional balance training and training balance in the balance trainer equally improved balance in subacute stroke patients. The balance trainer cannot replace a physiotherapist but it is a safe and efficient supplementary method.