Retrograde ejaculation (RE), known as one of the late complications of diabetes mellitus, is rarely a presenting symptom in the diagnosis of diabetes. A 30-year-old male presented with a progressive decline in ejaculate over 2-month. Lab results revealed a high random blood glucose level (425 mg/dL). A substantial number of sperm were found in the post-ejaculate urine specimens, confirming a diagnosis of RE. Further lab tests revealed an hemoglobin-A1c (HbA1c) of 12.7%, with negative results for antibodies to glutamic acid decarboxylase, insulin antigen-2, insulin receptor and islet cell, consistent with a diagnosis of type 2 diabetes mellitus (T2DM). Insulin glargine and oral anti-hyperglycemic agents were initiated. Also, imipramine and pseudoephedrine were prescribed for 4-week and then discontinued, as no positive effect on ejaculation was seen. At the 36-month follow-up, the patient had a normal glucose level with HbA1c 6.5%. However, RE persisted. RE is commonly seen as a late-stage complication among T2DM. We presented a rare case where RE was the first referred symptom of T2DM and RE persisted even after adequate control of glycemia.