Specimens of synovial tissue and articular cartilage removed at operations of patients with primary degenerative joint disease were scrutinized for defined histopathological parameters. The findings in the synovial membrane were subsequently compared as to frequency and intensity with identical parameters ascertained in specimens removed from patients with definite rheumatoid arthritis. These examinations disclosed the presence of synovial inflammatory features, although at lesser incidence and intensity than in rheumatoid arthritis; therefore the designation of arthritis is indicated. On the basis of the concurrently examined tissue specimens of the articular cartilage, and in consensus with the generally acknowledged start of the degenerative joint disease by disintegrating changes in the articular cartilage, the prefix of chondrosis is appropriate.