Introduction: Arthritis diseases in particular juvenile idiopathic arthritis (JIA) and rheumatoid arthritis (RA) are considered as autoimmune disorders, in which cytokines play a role in their pathogenesis. Methods: Serum levels of IL-1α and IL-1RA were assessed in 49 JIA and 43 and RA Iraqi patients, as well as 20 JIA controls and 17 RA controls. Results: Serum level of IL-1α was significantly (P ≤ 0.05) decreased in JIA patients compared to their controls (28.7 ± 1.7 vs. 52.5 ± 3.1) pg/ml, as well as in RA patients compared to their control (44.1 ± 2.5 vs. 51.2 ± 2.5) pg/ml. For IL-1RA, the serum level showed no significant difference between patients (JIA or RA) and their controls. Some significant variations were also observed when both groups of patients were distributed by disease severity scale, disease activity score and type of therapy and JIA patients by clinical subtypes. Conclusions: It was concluded that IL-1α was down-regulated in JIA and RA.