Diabetic neuropathy, and especially ocular paralysis (alone or associated with palsy of other cranial nerves) may be the first clinical manifestation of diabetes mellitus. The purpose of this work is to present the cases studied, which had an ocular paralysis as the first clinical manifestation, and which were affected by diabetes, unknown until that moment, clinical or latent, or were prediabetics. Thus, we believe that the existence of an ocular paralysis may be added to the other signs and symptoms mentioned as guiding elements for the diagnosis of the diabetic or prediabetic state. Our cases were carefully studied; they showed paralysis of III, IV and VI cranial nerves, isolated or, in 2 cases, associated with palsy of other cranial nerves. The existence of clinical or latent diabetes was confirmed by laboratory tests; the diagnosis of prediabetes was based on the usual criteria. Clinical evolution was identical to that observed in patients with clinically known diabetes. Some considerations on the pathogeny of diabetic ophthalmoplegia in relation to its sudden onset and to the rapid recovery of the cases studied are added.