Recurrent corneal erosion (RCE) is a common disorder causing ocular pain, tearing, photophobia, and visual impairments. Various factors such as ocular trauma, ocular surgery, corneal dystrophy, contact lens wear, and diabetes mellitus (DM) can cause RCE. The purpose of this study was to determine the causative factors and clinical course of RCE.We retrospectively examined 21 eyes of 21 patients with RCE and investigated the patients' background, type of treatments, and clinical course after the treatments. All patients were treated with eye drops, ocular lubrication, or contact lens bandage for the RCE.Among the 21 patients with RCE, 9 were caused by trauma (Trauma group), 8 by DM (DM group), 1 by bacterial corneal ulcer, 1 by lagophthalmus and bacterial corneal ulcer, 1 by bandkeratopathy, and 1 by eyelid tumor (one eye). The mean age of the patients was 57.8 years with a range 34-91 years. The mean duration from the trauma to the onset of RCE was 5.2 ± 5.0 months (mean ± SD). The time required for a complete recovery of RCE was longer in the DM group (10.3 ± 3.1 weeks) than in the Trauma group (2.7 ± 1.1 weeks, P < .01). The presence of DM was significantly associated with the recovery duration of RCE (r = 0.72; P < .01). Multivariate analyses showed that the recovery duration of RCE was associated with the presence of DM (odds ratio = 139.8, P = .04). On the other hand, the type of treatments had no effect on the recovery duration of RCE.These findings suggest that trauma and DM are important causes of RCE. Wound recovery after RCE may be delayed in patients with DM.