Forty-four patients were tested 2, 6 and 12 months after an isolated aortic valve implantation in order to evaluate the influence of training and vocational assistance on physical work capacity and the rate of reemployment. They were randomly allocated to a training group (A) or a control group (B). Training was carried out from the eighth to the twelfth week after operation and the socio-occupational status was evaluated. Training increased physical work capacity, expressed as cumulated work (CW), by 58 per cent (P less than 0.001), decreased the rate-pressure product (RPP) by 13 per cent (P less than 0.001) and the rate of perceived exertion (RPE) by 13 per cent (P less than 0.001) at the highest comparable work load. The CW was 38 per cent higher in the training than the control group after 6 (P less than 0.02) and 37 per cent after 12 months (P less than 0.025). After one year 81 per cent in group A and 65 per cent in group B were working (NS). Reemployment correlated significantly with the CW and inversely with the duration of sick leave prior to operation. Thus, physical training shortly after aortic valve operation rapidly and persistently improves physical work capacity while return to work is less influenced by training and socio vocational assistance.