Spontaneous pneumomediastinum (SPM) is defined as the presence of extraluminal gas in the mediastinal space without any clear traumatic cause. It has been reported in association with asthma exacerbation, emesis, childbirth, seizure, excessive shouting, drug inhalation and diabetic ketoacidosis (DKA). SPM complicated by DKA is infrequently accompanied with chest pain and DKA can lead to changes in respiratory rate and depth; this complication might be underestimated. Here, we report a 21-year-old male with throat pain on swallowing due to SPM complicated by DKA. Clinicians need to consider this complication in differential diagnoses.