Purpose To specify the risk factors for pseudophakic cystoid macular edema (CME) in patients with diabetes. Setting Kymenlaakso Central Hospital, Unit of Ophthalmology, Kotka, Finland. Design Prospective case series. Methods Patients with type 1 or type 2 diabetes having routine cataract surgery were evaluated. Spectral-domain optical coherence tomography imaging was performed before surgery and 1 month postoperatively. Results The study comprised 93 patients (95 eyes). The central retinal thickness increase was 9.7 μm ± 1.7 (SEM) in diabetic patients with no retinopathy, 22.7 ± 8.6 μm in those who had nonproliferative retinopathy, and 73.8 ± 37.4 μm in those who had proliferative retinopathy (P <.001). The central retinal thickness increase was greater in the eyes of diabetic patients with insulin dependence than in eyes of patients using noninsulin medication (21.9 ± 5.9 μm versus 8.3 ± 1.8 μm, P =.017). Serum hemoglobin A1c concentration and inversely, patient age, were associated with central retinal thickness increase, even after adjustment for confounding factors (r = 0.607, P <.001 and r = 0.417, P =.001, respectively). The central retinal thickness change was smaller in the eyes of patients who had a nonsteroidal antiinflammatory drug (NSAID) as their postoperative antiinflammatory medication than in eyes of patients who were not prescribed NSAID medication when retinopathy was analyzed as a covariant (8.2 ± 3.6 μm versus 13.6 ± 2.9 μm, P =.016). Conclusions Young patient age and poor glycemic control were risk factors for postoperative central retinal thickness increase. This study showed it is necessary to identify, effectively treat, and follow-up with patients with diabetes who are at a greater risk for pseudophakic CME.