This report includes 12 cases of juvenile rheumatoid arthritis seen through a period of 4 years of Unidad de Pediatría del Hospital General de México, S.S.A. An analysis is made on the etiology, prevalence, clinical symptoms, laboratory findings, radiology and treatment. The youngest patient was 3 years old and the oldest 14. Three groups were formed on the basis of the mode of onset; 4 patients were included in the systemic group, 7 in de polyarthritis and one in the monoarticular. All patients showed arthralgias and flogosis with joint disability in one or more joints; eleven patients developed joint deformity; 4 patients had fever and rheumatoid rash was detected during the course of the disease. Subcutaneous nodules were detected in one patient. Radiological abnormalities, compatible with juvenile rheumatoid arthritis, were found in all patients. Laboratory findings are discussed and a clinical correlation is made in order to emphasize the differences with adult disease. The principles of general treatment are analyzed including, medical, phychologic and rehabilitation programs. Pertinent literature is reviewed.