The tumor lysis syndrome (TLS) is a collection of metabolic abnormalities that occur in consequence of the release of intracellular contents following lysis of tumor cells. TLS occurs spontaneously or after chemotherapy. Spontaneous TLS is uncommon occurrence in multiple myeloma (MM). We define a case of a 70-year-old woman patient who was found to have MM with spontaneous TLS, following a compression fracture of the T-12 vertebrae. While serum uric acid and phosphorous levels were high, low calcium levels were identified. There were also acute kidney injury and metabolic acidosis. Upon the diagnosis of TLS, she was treated with hydration, allopurinol, sodium bicarbonate, and calcium gluconate. The improvement of her laboratory data was observed. We submitted this case in order to draw attention to the presentation of MM with spontaneous TLS.