This research is relevant, as AL-amyloidosis refers to a systemic type of disease characterised by aggregation of an improperly folded light chain of immunoglobulin, mainly in the heart and kidneys, causing organ failure. This study describes the clinical experience of introducing a patient with cardiac amyloidosis associated with multiple myeloma. A clinical case of a patient diagnosed with amyloidosis was considered. MRI signs of cardiac amyloidosis were confirmed due to the presence of concentric biventricular hypertrophy without dilation, atrial septal hypertrophy, a tendency to atrial dilation, thickening of valve flaps and atrial walls. Upon admission to the research institute, the patient had an anasarca. More accurate recognition of AL-amyloidosis by cardiologists allows prescribing earlier treatment and improving results. Conventional treatment of multiple myeloma and AL-amyloidosis includes a combination of dexamethasone with bortezomib and endoxan. Hematopoietic stem cell transplantation after taking high doses of melphalan has become another treatment option and has led to remission in some patients. The novelty of the study is that an example of a timely complete diagnosis and treatment of a combination of these two diseases was presented, as a result of which the patient has achieved a complete haematological and partial organ response to the underlying disease.