Introduction: Ambulatory unit of City Institute for Urgent Medical Care Belgrade (CIFUMCB) is a part of the primary healthcare system, and as such it is equipped with standardized diagnostic tools, electrocardiograph (ECG) being one of them. The diagnostic method of electrocardiography is performed on a daily basis in order to differentiate a variety of symptoms. Since the majority of patients coming to the ambulatory unit of CIFUMCB for help are first time visitors, unfamiliar to the physician who usually has no insight at all at their previous medical documentation, it is clear how this simple diagnostic tool becomes useful in revealing the underlying cause of a certain health issue. Aim: to present all kinds of patients’ complaints that required ECG diagnostic in the Ambulatory unit of CIFUMCB. Methodology: The electronic database of the Ambulatory Unit of CIFUMCB was utilized from January 1-22, 2015 on 206 examined patients. Health problems of the patients who had undergone ECG diagnosis were analyzed. A single patient could have had more than one health problem, in addition to the one of interest. Results: Among 206 examined patients nearly 50% had undergone ECG diagnostic. The reasons for performing ECG recording were: high blood pressure, chest pain and other difficulties such as shortness of breath, cough, rapid heartbeat, headache and dizziness, numbness in arms, nausea, and fever. Upon comparison of various health problems from different groups, usually from cardiovascular, respiratory and central nervous system origin, there was no statistically significant difference. Conclusion: The most common indications for ECG diagnostic among our patients were high blood pressure, followed by chest pain, irregular and rapid heartbeat, headaches and dizziness. Only 10% of these patients were referred to specialist for further assessment and treatment.