Objective To investigate the computed tomography (CT) characteristics of adrenal ganglioneuromas (AGNs) and to determine the ability of CT scanning to distinguish between large (>3 cm) and small (≤3 cm) AGNs. Methods This retrospective study searched the electronic medical record system of a hospital between January 2008 and July 2019 in order to identify patients with pathologically-confirmed AGNs that underwent three phases of CT scanning. The CT features were compared between large and small AGNs. Results A total of 30 patients with pathologically-confirmed AGNs were included in the study. The majority of patients (76.7%; 23 of 30) were asymptomatic and there were nonspecific symptoms in seven patients. The ‘pointed peach’ sign appeared in more than half of the patients (53.3%; 16 of 30). The CT value of the arterial phase, progressive enhancement, morphology and calcification in the CT images were found to be significantly different between large and small AGNs. Progressive enhancement was more likely to occur in small AGNs. Most large AGNs had irregular shapes, while small AGNs were likely to be round or oval with a smooth border. Calcifications were noted in large AGNs (42.9%; six of 14). Conclusion CT scanning can show many of the key imaging characteristics of AGNs used to distinguish between large and small AGNs.