OBJECTIVE: To test whether very early resumption of ambulation after femoral cardiac catheterisation is feasible and safe in patients with stable symptoms. DESIGN: Prospective study in a selected group of men and women undergoing elective cardiac catheterisation, with next day physical inspection. SETTING: Inpatient study. SUBJECTS: Two hundred consecutive ambulant patients submitted to diagnostic cardiac catheterisation through the femoral arterial route using 5F catheters: a femoral right heart study was done at the same time in 40 patients (20%). RESULTS: No patient had major complications during the study. Early ambulation was not allowed in two patients (1%) because of haematoma formation immediately after sheath removal, and in seven (3%) because of poor haemostasis or haematoma on inspection at 3 h. Early ambulation was interrupted in two patients (1%) because of transient arterial hypotension on standing in one, and the patient's preference in the other. Of 189 patients who resumed full ambulation at 3 h, one (0.5%) had a groin haematoma on discharge the next morning. Overall, haematoma 12 h after cardiac catheterisation was present in seven of the 200 patients initially included in the study (3.5%). None of the 191 patients with attempted early mobilisation had signs or symptoms of vascular complications one month or later after discharge. CONCLUSION: Supervised resumption of ambulation 3 h after uncomplicated cardiac studies with 5F femoral arterial catheters is safe and feasible in most ambulant patients undergoing elective cardiac catheterisation.