This cross-sectional study aimed to compare the effects of treatment with an atypical antipsychotic drug (olanzapine or risperidone) on quality of life (QoL) and to document adverse effects in 115 patients diagnosed with schizophrenia who attended the ambulatory service of Hospital Dr. João Machado, Natal, Rio Grande do Norte, Brazil. Socioeconomic, sociodemographic, and clinical variables were compared. The QoL Scale validated for Brazil (QLS-BR) was used to evaluate QoL, and adverse effects were assessed using the Udvalg for Kliniske Undersøgelser Side Effect Rating Scale. Data were analyzed using the χ(2) test and Student's t test, with a significance level of 5 %. Patients in both drug groups showed severe impairment in the occupational domain of the QLS-BR. Global QLS-BR scores indicated impairment among risperidone users and severe impairment among olanzapine users. The most significant side effects were associated with risperidone, including asthenia/lassitude/fatigue, somnolence/sedation, paresthesia, change in visual accommodation, increased salivation, diarrhea, orthostatic posture, palpitations/tachycardia, erythema, photosensitivity, weight loss, galactorrhea, decreased sexual desire, erectile/orgasmic dysfunction, vaginal dryness, headache, and physical dependence. QoL was impaired in patients using olanzapine and in those using risperidone. Risperidone use was associated with psychic, neurological, and autonomous adverse effects and other side effects.