OBJECTIVE To determine the utility of percutaneous transluminal angioplasty (PTA) of the femoropopliteal segment in patients with claudication and critical leg ischaemia (CLI). METHODS Longitudinal observational study. METHODS A university based vascular surgical centre. METHODS Ninety-five patients with stenosing or occlusive arterial lesions of the femoropopliteal segment underwent 52 primary PTA for claudication and 50 primary PTA for CLI. METHODS The procedure was considered haemodynamically successful when the increase of immediate postprocedural ABI was 0.15 or more. The criterion for haemodynamic success during follow-up was an ABI having not decreased by more than 0.15 from the immediate postprocedural level. The run-off arteries were graded according to the scoring system proposed by the SVS/ISCVS. RESULTS Among the technically successful procedures (83%), the haemodynamic success rate was 77% at 1 month, 55% after 1 year, and 51% after 2 years. The cumulative haemodynamic success rates were 83%, 66% and 61% in claudicants, and 70%, 42%, and 38% in CLI (p = 0.03). In patients with a run-off score < or = 7.5, the success rates were 84%, 67%, and 60%, respectively, whereas in those with a crural score > 7.5 these were 61%, 39%, and 39%, respectively (p = 0.04). CONCLUSIONS The haemodynamic results suggest that PTA to the femoropopliteal segment is seldom a procedure of choice for critically ischaemic legs with poor run-off. The run-off score is useful in identifying patients who may benefit from PTA.