: To investigate the aqueous humor and serum levels of selected cytokines and vascular endothelial growth factor (VEGF) in diabetic patients, implicating their role in the pathogenesis of diabetic eye complications.: Atotal of 65 patients (27 males and 38 females) who underwent cataract surgery were recruited into the study. The study group consisted of 30 cataract patients with type 2 diabetes mellitus, and this group was divided into two subgroups: 14 patients with diabetic retinopathy (DR group) and 16 patients without DR (NDR group). The control group consisted of 35 non-diabetic cataract subjects.: Patients in the DR group had significantly higher aqueous humor concentrations of interleukin (IL)-1β, IL-6, IL-8, IL-10, monocyte chemotactic protein (MCP-1) and VEGF. Likewise, serum concentrations of IL-1β, IL-6, IL-8, IL-12, TNF-α and IFN-γ were significantly higher in the DR group as compared to the controls. Aqueous humor concentrations of IL-1β, IL-8, MCP-1 and VEGF were significantly higher in the DR group as compared with the NDR group.: Our findings support the hypothesis that chronic inflammation and a disturbance of the immune system play important roles in the pathogenesis of diabetic cataract and DR.