The object of this study was to assess the feasibility of so-called ad hoc 5 F percutaneous transluminal coronary angioplasty (PTCA). This monocentric register included 200 consecutive procedures (233 lesions) of 5F PTCA by a femoral approach after a bolus of standard heparin (50 to 70 IU/kg). The population included 15.4% of stable angina, 29.4% of unstable angina, 11% acute phase, 13.5% post-revascularisation angina and 30.7% post-infarction cases. A successful procedure was defined as a good angiographic result without ischaemic complications. A failed 5F procedure was defined by the need to fall back on a 6F PTCA. The peripheral vascular complications were recorded. The lesions were stented in 77.4% of cases including 13.4% of direct stenting. There were 200 successful procedures (87%). The failures (N = 26) were mainly explained by the inability to cross chronic obstruction (N = 11). The ischaemic complications included 2 coronary bypasses (2 retrograde dissections of the left anterior descending artery) and 7 enzymatic increases without ECG changes. Fall back to 6F PTCA was required in 4 cases (1.7%) always because of the instability of the 5F catheter guide before the procedure. The quality of coronary contrast was estimated to be good. The vascular complication rate was low with 2% of communicating haematomas (N = 4). Therefore, 5F PTCA is feasible with failure and complication rates comparable to those reported with catheters of larger dimensions. One of its principal advantages is "ad hoc" angioplasty after 5F coronary angiography.