INTRODUCTION Light‑chain (AL) amyloidosis is the most common cardiac amyloidosis. Despite progress in treatment, early mortality remains a substantial problem in these patients. OBJECTIVES The aim of this study was to determine a clinical profile of patients diagnosed with AL amyloidosis in a cardiology department, as well as to define the cut‑off point for early mortality and identify predictors of early mortality in this population. PATIENTS AND METHODS The study included 30 patients (14 women; median age, 61.5 years) with AL amyloidosis confirmed by echocardiography and biopsy of 2 organs. RESULTS Six patients were diagnosed with stage II amyloidosis according to the Mayo 2004 classification, and 24 patients-with stage III. Early mortality was defined as death during 102 days after diagnosis and was observed in 14 patients. Patients who died earlier were younger and more frequently reported a weight loss of more than 10 kg and orthostatic hypotension than patients who died later. Moreover, they had higher concentrations of high‑sensitivity troponin T and N‑terminal pro‑B‑type natriuretic peptide (NT‑proBNP) and worse left and right ventricular (RV) contractility. In the Cox models, the age of less than 64 years, NT‑proBNP levels exceeding 4968 pg/ml, RV end‑diastolic diameter of less than 34 mm, and tricuspid annular plane systolic excursion lower than 13 mm were significant predictors of mortality within 102 days after diagnosis. CONCLUSIONS We presented the results of the first Polish prospective noninterventional study on AL amyloidosis diagnosed in the cardiology department. We found that patients have advanced disease at the time of diagnosis. Younger age, impaired RV function, and higher concentrations of cardiac markers are predictors of worse prognosis.