Introduction: Widespread opinion that penetrating chest injuries are more urgent, in terms of treatment and care, contributed to underestimation of the urgency of blunt chest trauma, which in most cases is treated conservatively. It remains an open question frequency when the injuries of the heart and pericardium are not timely diagnosed and surgically treated. Aim: To demonstrate the importance of well-timed surgical treatment of blunt chest trauma, when coupled with cardiac and pericardial injuries. Methods: At the Thoracic Surgery Clinic of the University Clinical Centre Banja Luka, Bosnia and Herzego vina, during period of 10 years (01.01. 2008 – 31.01.2018.), the total of 66 patients were treated for urgent thoracotomy due to clinically and radiologically unclear findings after blunt chest trauma. In general, diagnostic examinations, apart from laboratory analysis, included radiological imaging and Multi Slice Computed Tomography (MSCT) of the chest, followed by an ultrasound of the heart in cases when sternum was injured or when pericardial tamponade was suspected. Results presented in the study where obtained from the retrospective analysis of patients data. This work presents a retrospective observational cross-sectional study, which results in the assessment of the correctness of a particular diagnostic test. Statistical methods used: descriptive statistics, counting measures (frequencies and percentages), central tendency measures (arithmetic mean), variability measures (standard deviation). Results: Sixty six patients were treated with urgent thoracotomy after a blunt trauma of the chest due to the unclear clinical and radiological finding. In the case of 11 patients (10 men and 1 woman), presenting 16.6% of the total sample, pericardial and cardiac injuries were detected and treated intraoperatively. Further, in the case of the one patient, pericardiotomy and suturing of the right heart chamber where performed, with the creation of a pericardial window. Transthoracic echocardiogram was not used as the primary screening module, but rather as a diagnostic test for patients who had unexplained hypotension and arrhythmia. Radiographs of the chest showed cardiomegaly with or without epicardial fat pad sign suggesting a pericardial effusion. Conclusion: Blunt cardiac and pericardial injuries represent a serious therapeutic problem, which, if not treated properly, result in a high mortality rate. Echocardiography is the primary diagnostic method for initial detection of pericardial effusion. Pericardial fluid first accumulates posterior to the heart, when the patient is examined in the supine position. As the effusion increases, it extends laterally and with large effusions the echo-free space expands to surround the entire heart. The size of the effusion may be graded as small ( echo free spaces in diastole <10 mm, corresponding to approxymately 300 ml), moderate (10-20 mm, corresponding to 500 ml), and large ( >20 mm, corresponding to >700 ml). When the ability of the pericardium to stretch is exceeded by rapid or massive accumulation of fluid, any additional fluid causes the pressure with the pericardial sac. Early recognition, pericardiotomy with pericardial window creation and/or ventricular rupture suture remain the “gold standard” in the treatment of blunt cardiac and pericardial injuries.