Thirteen patients are described in whom Still's disease began after age 15. All had objective evidence of arthritis, and 10 developed chronic synovitis of larger joints, especially the wrists. A characteristic evolution of roentgenographic changes was observed in 7 patients. Carpometacarpal and intercarpal joint spaces became selectively narrowed without erosions, and bony ankylosis eventually occurred. These roentgenographic changes may be a valuable clue to the diagnosis of Still's disease, regardless of the age at onset.