Primary divergence insufficiency is a generally benign condition affecting the elderly. Many patients have spontaneous resolution of the double vision within few months, so it is advisable to postpone strabismus surgery and follow the patient. It is also important to perform a differential diagnosis in order to rule out other causes of distance esotropia. For this purpose, a thorough history and careful ophthalmologic/strabologic examination should be performed. Clinical neurological evaluation is an effective tool to distinguish between patients with primary and secondary forms of divergence insufficiency. When making the diagnosis, special attention should be paid to the presence of nystagmus and the role of neuroimaging studies.