Juvenile rheumatoid arthritis is a disease characterized by chronic inflammation in one or more joints; it affects children and adolescents up to 18 years of age. This disease may cause significant skeletal joint destruction, and the temporomandibular joint, like other joints, may become severely affected resulting in aberrant mandibular growth, abnormal dentofacial development, and/or altered orofacial muscle function. Methotrexate is the most common remittive agent used in juvenile rheumatoid arthritis to modify the course of inflammatory destruction of peripheral joints. The purpose of this study was: (1) to evaluate the effect of methotrexate therapy on the prevalence of temporomandibular joint lesions and aberration in craniofacial development in children afflicted with juvenile rheumatoid arthritis; (2) to further examine the relationship between the temporomandibular joint/cephalometric findings and rheumatologic data (ie, age at onset, duration of disease); and (3) to evaluate further pauciarticular- and polyarticular-onset disease in juvenile rheumatoid arthritis and the prevalence of temporomandibular joint lesions and facial dysmorphology. The following information was obtained from 45 patients with juvenile rheumatoid arthritis: (1) routine rheumatologic clinical examination data; (2) anamnestic temporomandibular joint evaluation data; (3) clinical temporomandibular joint examination data; (4) lateral cephalometric measurement data; (5) posteroanterior cephalometric measurement data; and (6) individually corrected axial tomographic data. The results demonstrated the following: (1) radiographic evidence of condylar degeneration was apparent in 63% of all patients with juvenile rheumatoid arthritis with pauciarticular patients showing less temporomandibular involvement than polyarticular patients; (2) polyarticular juvenile rheumatoid arthritis patients receiving methotrexate showed less severe temporomandibular joint involvement than the polyarticular patients not receiving methotrexate; (3) the craniofacial structure was affected to a greater extent in the polyarticular form of the disease; (4) the craniomandibular index scores were significantly greater in the polyarticular group; (5) vertical height asymmetry and chin deviation were noted in more than 50% of the patients; and (6) there was a correlation between the severity of condylar lesions and cephalometric findings (ie, mandibular retroposition, posterior rotation, smaller ramus and mandibular dimensions) and the onset and duration of the disease. In conclusion, under the conditions of this study, methotrexate therapy was effective in minimizing temporomandibular joint destruction and craniofacial dysmorphology in juvenile rheumatoid arthritis patients with the polyarticular form of the disease.