Objective: Several cytokines play a role in the production of autoantibodies and the pathogenesis of rheumatic diseases including systemic lupus erythematosus (SLE),  rheumatoid arthritis (RA) and systemic sclerosis (SS). This study investigated serum concentration of the proinflammatory Th₁ cytokine; IL₁₈ and its inducer IFNg, the study also investigated serum concentration of proinflammatory Th₂­ cytokine; IL₁₃, to explain the role of Th₁ and Th₂ in the pathogenesis of autoimmune rheumatic diseases (SLE, RA and SS) Patients and methods: IL₁₈, IFNg and IL₁₃ levels were evaluated by enzyme linked immunosorbent assay (ELISA). Four groups were included in this study. Group I: Comprised (15) patients of SLE. Group II: Comprised (15) patients of RA. Group III: Comprised (15) patients with SS. Group IV: Control group consisted  of (15) sex and age matched healthy controls. Results: Serum levels of IL₁₈ was significantly higher in SLE (3138.200± 1413.096 pg/ml)& RA(3336.667± 921.839 pg/ml) than control group(86.647± 35.370 pg/ml ), while IL_18­ in SS had no statistically significant difference between patients (103.634± 50.593 pg/ml)  and control group (86.647± 35.370 pg/ml).The cut off level  was 257.75 pg/ml .                             IFNg was significantly higher in SLE patients (5.439±1.430 IU/ml) and RA patients (2.973± 0.598 IU/ml ) than control group(0.580 ± 0.234 IU/ml) ,while IFNg  in SS had no statistically significant difference (0.592± 0.245IU/ml) than control group (0.580 ± 0.234 IU/ml) .The cut off level was1.2 IU/ml . As regard IL₁₃ it  was significantly higher in SLE patients (55.673±6.892 pg/ml) ,RA patients (59.587±12.183 pg/ml) and SS (61.550± 12.047 pg/ml) than control group (21.427± 7.274 pg/ml ) .The cut off level was 44.4 pg/ml .There was significant positive correlation of IL₁₈/ IL₁₃ and IFNg / IL₁₃  ratio in SLE and RA , while significant negative correlation of IL₁₈/ IL₁₃  and IFNg / IL₁₃ ratio in SS. Conclusion: There was a significant increase of both Th₁ cytokines (IL₁₈ and IFNg) and Th₂­ cytokine (IL₁₃) in SLE and RA with Th₁ predominance,while predominance of Th₂­ cytokine (IL₁₃) in SS than  Th₁ cytokine (IL₁₈ and IFNg). This result suggests that IL₁₈, INFg and IL₁₃  could be involved in the pathogenesis of autoimmune rheumatic diseases.