Background: Diagnosis of lateral medullary syndrome (LMS) is often delayed due to elusive clinical presentations and frequently non-revealing neuroimaging tests. We aimed to investigate the use of ipsilateral vocal cord paresis (VCP) identified on neck computed tomography angiography (CTA) as an early diagnostic sign for LMS. Methods: Medical records were queried for patients admitted with LMS between 1/2012 and 10/2020. A control group of patients undergoing CTA for transient or no neurological symptoms was matched for sex and age. Clinical data were collected by a stroke neurologist. Two neuroradiologists independently and blindly assessed CTA images for radiological signs of VCP. Results: Fifteen LMS and 15 control patients were included in the analysis. Median time from arrival to LMS diagnosis was 29.4 h [IQR 7,47] and twice as long in patients who suffered aspiration pneumonia. Thrombolysis rate was 0% in LMS patients versus 14.5% in general stroke patients. Dysphonia was noted in the emergency department in three (20%) patients, whereas all 15 patients had radiological signs of VCP on CTA. Medialization of a true vocal cord was the most sensitive (100%) and specific (80–87%) sign for LMS, with good inter-rater agreement (kappa 0.66). Timely detection of VCP on CTA could have shortened median time to LMS diagnosis by 14 h and enabled thrombolytic therapy in 3 (20%) patients. Conclusions: VCP on CTA is a valuable sign for the diagnosis of LMS. If detected early, it may enable reperfusion therapy and prevent aspiration pneumonia, consequently saving life and diminishing disability.