Introduction: The occurrence of the atypical antipsychotics was imposed by the necessity of obtaining a therapeutic control more efficient in schyzophrenia, by limiting side effects. The psychopharmacological mechanisms of action of the atypical antipsychotics are different, influencing the profile of some side effects. Study purpose: The evaluation of the incidence and severity of the adverse non-extrapyramidal effects at the administration of 8 of the atypical antipsychotics and an atypical antipsychotic. Material and Method: A clinic, longitudinal, prospective, open, comparative study was done regarding the differences of security and tolerance between the atypical antipsychotics and the latter versus haloperidol. The study had been carried on for 1 year, on a group of 180 patients diagnosed with schizophrenia, according to the DSM IV-TR criteria. Groups of 20 patients were administered one of the atypical antipsychotics and a group of 20 patients was administered haloperidol. Results: The percentage rates of mild and severe nonextrapyramidal occurred after the administration of each atypical antipsychotic was analyzed; these were compared both between them and with the percentage rates of nonextrapyramidal side effects ESP determined by haloperidol. It was specified the moment of occurrence and the dose at which occurred. The non-extrapyramidal side effects that impose the stopping of the study were: weight gain, carbohydrates and / lipid metabolism disorders, cardiac and endocrine disorders. Conclusions: - The most severe extrapyramidal side effects were presented by olanzapine, sertindole, amisulprid and clozapine. - The lowest percentage of severe extrapyramidal side effects was presented by ziprasidone, aripiprazole and risperidone.