Background: Eales' disease (ED) is an idiopathic obliterative vasculopathy that usually affects the peripheral retina of young adults. The aim of this study is to investigate Th1/Th2 serum cytokine profiling in patients with ED. Methods: This study included 30 male patients with ED and 10 healthy controls. The ED patients were divided into two subgroups: the vitreous haemorrhage (VH) group (n = 18) and non-vitreous haemorrhage (NVH) group (n = 12). Sixteen patients (six from the VH group and 10 from the NVH group) received glucocorticoid treatment for three months and were followed for six months. Levels of six cytokines including interferon-gamma (IFN-γ), tumour necrosis factor-alpha (TNF-α) and four interleukins (IL-2, IL-4, IL-5 and IL-10) in the serum samples were determined by Luminex assays. Results: Compared to controls, ED patients showed significantly higher levels of IL-10 and TNF-α, increased IFN-γ/IL-4 (Th1/Th2) ratio, and lower levels of IL-4 (p < 0.05). Glucocorticoid treatment caused a restoration in the cytokine levels and the IFN-γ/IL-4 ratio. Multivariate analysis revealed that reduced IL-4 (less than 4 pg/ml) and elevated IL-10 (greater than 4 pg/ml) levels were independent predictors of ED with odds ratios of 0.024 (95% CI, 0.002–0.255; p = 0.002) and 12.108 (95% CI, 1.045–140.233; p = 0.046), respectively. Conclusion: The findings demonstrate for the first time that there is an imbalance of Th1/Th2 cytokines in ED patients, which can be reversed by glucocorticoid treatment. Additionally, both IL-4 and IL-10 might represent potential diagnostic markers for the disease.