Two distinctly different substitution principles are commonly used in haemophilia: treatment at bleeding episodes only referred to as on-demand treatment, and prophylactic factor administration. The aim of the cross-sectional study which was undertaken in young patients suffering severe haemophilia A was to challenge our hypothesis that on-demand treatment is inferior to prophylactic substitution in prevention of chronic joint disease at young age. The method involved an investigation of 40 patients from Russia (n = 27) and Denmark (n = 13) born between 1975 and 1990 with no history of inhibitors; Russian patients had exclusively received factor VIII on demand, while Danish patients were managed with prophylactic treatment during a mean period of 16 years since median age of 5 years. The study endpoints were clinical joint scores, Quality of Life scores and functional independence scores. Matched by identical age (±1 year) 13 Danish and 13 Russian patients were compared, while 14 age similar Russian patients served as controls. Demographic data among all groups were quite comparable. The results are that Russian patients presented with clinical joint scores at 27 ± 8.5 (mean ± SD) while matched Danish counterparts scored 3.8 ± 5.3 (mean ± SD), differences being highly significant. The number of joint bleeds in recent 5 years were 199.5 ± 135 (mean ± SD) vs. 8.1 ± 8.7 (mean ± SD). Likewise, Quality of Life and functional independence scores were significantly higher in patients on prophylaxis as compared to on-demand treatment. In conclusion, the study outcomes confirmed our hypothesis. Longer term prophylactic factor administration during childhood and adolescence prevents joint destruction.