In this retrospective study, we report the clinical and biochemical features of diabetic ketoacidosis (DKA) in adult patients who were managed at the Instituto Nacional de la Nutrición during a 6.5 year period. There were 98 episodes in 46 patients: 22 females (48%) and 24 males (52%). Six patients (13%) had four or more episodes of DKA. Thirty five percent of the events occurred in patients with IDDM; 48% in "late onset" NIDDM: 9% in "early onset" and 9% in classical NIDDM. Infections as the precipitating factor in 41% of episodes of DKA were the initial manifestation of diabetes. We compared our results with those from other reported series, finding no differences among them. The mean anion gap in our series was 30.4. Main complications identified were hypokalemia in five cases, hypoglycemia in four cases, hypernatremia in four cases, and acute pulmonary edema, ventricular fibrillation, neurological deficit and coma in one case each. There were three deaths (6.5%) in the whole group. To our knowledge, this is the largest series on adult patients with DKA reported in our country in the last decade. The obtained results may help evaluate prospectively the impact of different diagnostic and therapeutic strategies in the management of DKA.