OBJECTIVE: To establish the feasibility and safety of an appropriately trained clinical nurse specialist performing diagnostic cardiac catheterisation. DESIGN: Non-randomised retrospective comparison between the first 100 and second 100 consecutive investigations by a clinical nurse specialist and 200 consecutive patients investigated by two cardiology registrars over a similar period. SETTING: Regional cardiac centre performing 3200 catheterisation procedures per annum. PATIENTS: 200 patients undergoing routine (non-emergency) cardiac catheterisation for investigation of ischaemic heart disease. MAIN OUTCOME MEASURES: Procedural complications, image quality, fluoroscopy times. RESULTS: Satisfactory diagnostic images in all nurse specialist cases with no deaths and two complications (coronary artery dissection and femoral pseudoaneurysm). Procedure duration and fluoroscopy times slightly shorter for clinical nurse specialist by 3 and 1.6 minutes, respectively (P < 0.05). CONCLUSIONS: Non-medical practitioners can be trained to perform straightforward cardiac angiography in low risk patients with consultant supervision, as for cardiology registrars. With important restrictions such posts may have a limited role in supporting future consultant based services.