Cardiologists and generalists have been reported to diverge in terms of their self-reported use of angiotensin-converting enzyme (ACE) inhibitors, but information on their actual use of ACE inhibitors has been lacking. In order to assess ACE inhibitor use in patients with heart failure in a teaching hospital and any differences between specialties we studied all patients in the Western Infirmary of Glasgow between 1 April and 1 October 1996 with an echocardiogram showing moderate or severe left ventricular systolic dysfunction (n = 236). We found that most patients were on an ACE inhibitor (66%), 12% had been tried but found to be intolerant, 10% had not been tried because of a contraindication, but 12% had not been tried despite no contraindication. Of those on treatment, 58% were on a dose used in a major survival study (38% of all patients). Most patients were treated by a cardiologist (64%). Of these, more were on an ACE inhibitor (77% vs 53%, p < 0.01), fewer had been tried but found intolerant (11% vs 18%), and fewer had never been tried (11% vs 29%, p < 0.01), irrespective of whether they had a contraindication (5% vs 18%, p < 0.01) or not (6% vs 12%). More were on a dose used in a major survival study (48% vs 31%, p < 0.05). We conclude that, despite improvements over time, ACE inhibitors are still under-used, sometimes without good reason. There are also differences in the use of ACE inhibitors between cardiologists and generalists which may affect outcome, and could affect resource utilisation.