Bens-Jones protein is a group of immunoglobulins that can be detected in urine. Their appearance in the urine is most often typical for multiple myeloma.

First time this protein has been described by the English physician Henry Bens-Jones while examining the urine test and named after accordingly.

Bens-Jones protein is determined in 50-70% of multiple myeloma population, 30-40% of Waldenstrom's macroglobulinemia population and in 90% of primary amyloidosis population. Other conditions when Bens-Jones protein may be observed in urine are lymphoma, leukemia (mainly chronic lymphocytic leukemia or plasma cell leukemia), pancreatic cancer, medullary thyroid carcinoma, benign gammopathy of undetermined significance.