The prognosis in 52 patients with juvenile rheumatoid arthritis (JRA) was studied. There were 35 cases of systemic onset, 12 of polyarticular onset and 5 of pauciarticular onset. Thirteen systemic cases developed a polycyclic course with chronic polyarthritis. Many monocyclic JRA in systemic cases subsided within 1 year. There were no instances of polyarticular cases or pauciarticular cases that shifted to other type. However, there were many cases with a long active polyarticular JRA and with remission at an early stage in the pauciarticular type. The stage and class were I or II in 90% of cases with a good prognosis for the joints, but there were some serious cases. Transient carditis or iritis which developed at an early stage subsided later. The intractable systemic cases had drug-induced complications. The cases with steroid-induced complications tended to be chronic. One death in a systemic case was caused by hepatic failure.