A 19 year old presented with a progressive decline in ejaculate volume over 2 weeks, followed by a complete absence of ejaculate emission. A post-ejaculatory urine specimen demonstrated spermatozoa confirming a diagnosis of retrograde ejaculation. Investigations revealed a raised blood glucose level of 24.5 mmol/L and HbA1c >15%, with positive tests for anti-GAD antibodies and anti-IA2 antibodies consistent with a diagnosis of Type 1 diabetes mellitus. Retrograde ejaculation in diabetes is associated with autonomic neuropathy and is a late feature of the disease. This case is unique with retrograde ejaculation being the primary presenting symptom of Type 1 diabetes mellitus.