Purpose: To investigate the role of serum uric acid and leukocyte counts and ratios as predictors of clinical outcomes of intravitreal bevacizumab in diabetic macular edema. Methods: In this prospective study, the patients were treated with three monthly intravitreal bevacizumab. The correlation of serum uric acid and immune cell indices with the changes of best-corrected visual acuity and central macular thickness at the end of month 3 were evaluated through univariate and multivariate linear regression analysis. Results: A total of 80 eyes from 80 diabetic patients were included in the study. The difference of uric acid level and immune indices between groups with different retinopathy severity was not statistically significant (p > 0.05). Lower duration of diabetes (p = 0.045), monocyte count (p = 0.021), and uric acid level (p < 0.001) were correlated with larger improvement in visual acuity at 3-month visit. Higher logarithm of the minimum angle of resolution of baseline visual acuity (p = 0.007), lymphocyte count (p = 0.008), lymphocyte to neutrophil ratio (p < 0.001) and lymphocyte to platelet ratio (p < 0.001) were correlated with larger improvement in visual acuity at 3-month visits. According to multivariate analysis, baseline logarithm of the minimum angle of resolution (r = 0.125, p = 0.009), duration of diabetes (r = -0.216, p = 0.047), lymphocyte to neutrophil ratio (r = 0.712, p < 0.001), lymphocyte to platelet ratio (r = 0.238, p < 0.001), and uric acid level (r = -0.397, p < 0.001) were the significant predictors of changes in visual acuity in our subset of patients. Conclusions Serum uric acid and leukocyte counts and ratios may predict the response of diabetic macular edema to intravitreal injection.