Primary light-chain (AL) amyloidosis is a plasma cell dyscrasia associated with the deposition of immunoglobulin-derived amyloid in multiple organs. In the heart, this results in an infiltrative cardiomyopathy, with increased left ventricular wall thickness, normal or decreased left ventricular (LV) cavity size and congestive heart failure. Cardiac involvement is a major determinant of prognosis of AL amyloidosis. We report a patient with cardiac amyloidosis proven by cardiac biopsy, and aim to point out at transthoracic echocardiography as the hallmark of diagnostics. Echocardiography revealed increased LV thickness at 20mm, impaired LV ejection fraction (EF) at 35%, enlarged atria, transmitral deceleration time at 156 ms and increased E/A ratio at 4.25. Early diagnosis and intervention can have a significant impact on the patient's response to treatment, especially when the underlying condition involves a malignancy or infiltrative disorder. Standard transthoracic echocardiography as a noninvasive diagnostic tool is valuable and has a significant role in diagnosis and prognosis.