Objective. To develop and evaluate clinical decision support software (CDSS) to aid physicians treat patients with chronic heart failure (CHF). Methods. The CDSS was developed after discussions with a multidisciplinary panel. Evaluation was performed in three stages over a 6 month period including an editorial check, one-to-one interviews with potential users and educational meetings with general practitioners (GPs), junior doctors and medical students during which the CDSS was assessed in a cross-over design against paper guidelines. Opinions of the CDSS and the computer literacy of the participants were assessed by questionnaire. Results . There were several changes to the CDSS at various stages of development and evaluation. One-to-one interviews generated extensive qualitative feedback. GPs had lower computer literacy scores than junior doctors and students (both p<0.01p<0.01). There were small trends when comparing the CDSS with paper guidelines. GPs scored less well (CDSS 75% vs. 80%, p=0.41p=0.41), while junior doctors and medical students appeared to improve their scores (72%–84%, p=0.32p=0.32 and 66%–77%, p=0.19p=0.19, respectively). Most (70%) found the CDSS more useful than the written guidelines. Conclusion. Development of CDSS using guidelines and expert opinion requires a multidisciplinary iterative process of feedback and software adaptation. Barriers to implementation identified include lower computer literacy among GPs, a lack of complexity within CDSS in addressing non-medical needs of patients and a reluctance among medical staff to consult guidelines during patient consultations. Improving computer skills, integrating CDSS into referral pathways and requests for investigations may be ways of enhancing use of this emerging technology.