Abstract: Provided are formulations of anti-CD38 antibodies suitable for subcutaneous administration to a subject in need thereof. The formulations include a high concentration of antibody, a viscosity lowering agent, a stabilizing agent, a buffering agent and a surfactant. In certain embodiments, the viscosity of the solution is at most 25 mPa·s, and the pH of the solution is 5.9 to 7.0. In certain embodiments, the anti-CD38 antibody is isatuximab. The formulations will find use in treating CD38+ hematological malignancies, including multiple myeloma, as well as autoimmune and inflammatory diseases, in humans.