Atypical antipsychotics is known to cause a number of adverse metabolic effects, including weight gain, insulin resistance, hyperglycemia, dyslipidemia and type 2 diabetes mellitus. Aripiprazole is an new atypical antipsychotic that has a safer profile compared to other antipsychotic medications with regard to its effect on weight gain, glucose tolerance and prolactin level. However, recently there have been few case reports on hiperglisemia and diabetic ketoacidosis related by aripiprazole. In this report, we discuss a clinical case with tip 1 diabetes mellitus that developed hiperglisemia during aripiprazole treatment.