This retrospective clinical notes review assesses whether serum angiotensin converting enzyme (ACE) is useful in the diagnosis of sarcoidosis in patients presenting with uveitis. There were 1035 consecutive subjects presenting with uveitis as part of baseline investigations had a serum ACE. The study assesses the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of elevated serum ACE. The mean age of the patients was 41.7 years and 56.1% were female. Sarcoidosis was found to be the underlying cause for the uveitis in 110 patients (10.6%). This was most commonly found in black female adults who presented with intermediate uveitis or pan uveitis. Serum ACE was found to be raised in 196 patients (18.9%), 85 patients were diagnosed with sarcoidosis (true positive 77.3%) and in 111 patients an alternative diagnosis was made (false positive 12%). In adults, the sensitivity of serum ACE was 78.1%, specificity 90% and PPV 43.6%, however the NPV was 97%. Serum ACE is less useful in diagnosing sarcoidosis in paediatric patients. Therefore, in adults a normal serum ACE eliminates the need of further screening tests such as chest x-ray due to the very high NPV.