Unit for exercise electrocardiography in Mostar Clinical Hospital egzists more than 35 years. Master step tests were introduced first, on improvised moveing stairways with successive ECG recording on classical 3 or 6 channel equipment. After, unit was supplied with bicycle-ergometer without continutaed monitoring and later with continuated monitoring with exercise cut-off in a phase of recording. In 1984 TRENDMIL was obtained with computer software and monitoring, and its been used up to now. We perform exercise tests in estimation of coronary disease and in rare occasions in following of patientns functional status and effects of treatment. In technical maintenance of exercise electrocardiography equipment as in prepareing and education of patients for that examination, nurse plays important role. During 2000. We performed 265 tests. 165 patients were male and 109 female. With age to year 40 we had 43 patients (16.2%), with age 40-60 we had 154 patients (58.1%) and older than 60 were 168 (25.6%) patients. Nurse is involved in collecting of patients data: dateing of patients, collecting findings: laboratory and X-ray, internal medicine specialist examination, ECG. Very important is role of nurse in correct placement of electrodes, skin cleaning and hair removeing before procedure and also in placeing of contact webs (important for good signal during test). Important role of nurse is in follow up of monitoring, recording disturbances, reacting on fall of blood pressure, malignant rhythm disturbances and interventing with therapy of DC shock.