The size of adrenal incidentalomas has important implications for diagnosis and management. Recommendations from endocrine societies do not all correlate with regard to adrenal incidentaloma size. Therefore, the aim was to compare adrenal incidentaloma size recommendations between different endocrine societies and the reasoning for these recommendations.Eight different international guidelines were reviewed and compared. The smaller the size of the incidentaloma, the lower the risk for malignancy. The majority of guidelines consider 4 cm as the cut-off, but there are discrepancies. Size indications for laparoscopic adrenalectomy have a wide range from less than 4 cm up to 12 cm. The follow-up period of adrenal incidentalomas, as well as what is considered significant growth over that period, varies between the recommendations.Therefore, the clinician should be aware of the differences when managing a patient with adrenal incidentaloma. There are discrepancies in size considerations with regard to significance, treatment options, optimal follow-up period, and further management.