Background A chest pain stipulates great clinical, methodological, economic, social, psychological problems. There are dozens diseases of various organs manifested by chest pain. Diagnostic errors happen often. Suggested Differential Diagnostic Algorithm (DDA) is a certain universal intellectual tool, which could facilitate the chest pain problems solving. Objective The Chest Pain (CP) DDA creation for effective differential diagnostics of diseases accompanied with chest pain for use primarily in a polyclinic, ambulance, ED. Methods Presented here new CP DDA is developed by the author for the chest pain syndrome as the original intellectual method of clinical thinking based on the problem-oriented algorithmic approach. Results The retrospective posthumous study of 127 case records of patients who died of a fatal heart attack was performed too. The errors of the retrospective algorithmic diagnoses based on the symptoms/signs written down in 127 case records were in ~4 times less, than at the collective posthumous clinical diagnosis, in 6,3 times less errors than lifetime diagnoses in cardiological clinics, and ~9 times less than antemortem diagnoses in the admission department. The main result is the new chest pain DDA presentation. Conclusions By means of presented DDA every physician and medical student can diagnose successfully of 48 diseases manifested by chest pain.