AIM:To compare the effects of non-steroidal anti-inflammatory drugs（NSAIDs） at different administration timing on central foveal thickness following cataract surgery in patients with cataracts and cataracts with diabetes. METHODS:Ninety patients were divided into two groups randomly in this prospective,randomized study. Each group had 23 patients with cataracts and diabetes and 22 patients with cataracts only.These groups were enrolled for cataract surgery from Feb.2009 to Sep.2009 without any postoperative complications.In groupⅠ（trial group）,pranoprofen was administered one day before surgery in 45 eyes.In groupⅠ（control group）, pranoprofen was administrated one day following cataract surgery in 45 eyes.All patients were treated with topical tobramycin and dexamethasone one day after surgery. Central foveal thickness was measured via pptical coherence tomography（OCT） during the final week before surgery as well as on the 7^th day and 30^th day after surgery. RESULTS:No significant differences were found in central foveal thickness between the groups on the 7^th day after surgery,however,there were significant differences in central foveal thickness between groups on the 30 day after surgery.There were no significant differences in central foveal as well as retinal thickening of the macular fovea in patients purely with cataracts on the 7^th and 30^th postoperative day.In the patients with cataracts and diabetic disease,significant differences were found in central foveal thickness and retinal thickening of macular fovea compared to patients with only cataracts（P<0.05） on the 7^th and 30^th day after surgery. CONCLUSION:Pranoprofen administrated preoperatively has better effects on alleviating retinal thickening of fovea centralis compared to its postoperative administration in the patients with cataracts and diabetic disease.Our findings suggest that preoperative administration of pranoprofen should be taken into account when we treat cataract patients with diabetic disease.