The condition of spontaneous hyperventilation tetany has received some attention recently, and in many cases it has been impossible to demonstrate adequate biochemical changes to account for the tetanic manifestations, which so closely resemble the more recognized clinical types of tetany. The reason for the apparent spontaneity of the attacks has remained obscure beyond the general trend to recognize it as “functional” in most cases. In view of this recent interest, and of the atypical clinical manifestations in this case, the following observations on a single patient are put on record. A few previous cases treated at the Maudsley Hospital, but differing from the present one in the absence of loss of consciousness during the attacks, are also briefly reported.