Cardiac involvement in amyloidosis is associated with a poor prognosis. Data on the burden of arrhythmias in patients with cardiac amyloidosis (CA) during hospitalization is lacking. We identified the burden of arrhythmias using the National Inpatient Sample (NIS) database from Jan 2016- Dec 2017. We compared patient characteristics, outcomes, and hospitalization costs between CA patients with and without documented arrhythmias. Out of 5,585 hospital admissions for CA, 2,020 (36.1%) had concurrent arrhythmias. Propensity-score matching for age, sex, income, and comorbidities was performed with 1,405 CA patients with arrhythmias and 1,405 patients without. The primary outcome of all-cause mortality was significantly higher in CA patients with arrhythmia than without(13.9% vs. 5.3%, p-value <0.001). Atrial fibrillation (AF) was the most common (72.2%) arrhythmia in CA patients with concurrent arrhythmia. The secondary outcomes of AF-related mortality (11.95% vs. 9.16%, P-value = 0.02)and acute and acute on chronic as heart failure (HF) exacerbation (32.38% vs. 24.91%, P-value <0.0001) were significantly higher in CA and concurrent arrhythmia compared with CA patients without. The total length of hospital stay (6[3-12] vs. 5[3-10], P-value <0.001) and cost of hospitalization was ($ 15,086[7,813-30,373] vs. $ 12,219[6,865-23,997], P-value = 0.001) were significantly greater among CA with arrhythmia compared with those without. These data suggest that the presence of arrhythmias in CA patients during hospital admission is associated with a poorer prognosis and may reflect patients with a higher risk of HF exacerbation and mortality.