Carbon monoxide (CO) poisoning can cause severe neuropsychiatric disorders. However, no sufficient attention has been paid to this issue in literature. The definition, treatment and clinical course of neuropsychiatric symptoms that occur especially after poisoning are not known exactly. In the studies conducted to date, neurological symptoms, cognitive, mood and personality disorders have been observed in the cases years after CO poisoning. However, the hypotheses regarding the etiopathology of long-term neuropsychiatric findings have not clarified the subject completely. The interaction of environmental and neurobiological complex factors related to the patient's clinical symptomatology may be a risk factor for the emergence of long-term neuropsychiatric disorders. In this study, a 45-year-old female patient who presented to our clinic with late-onset psychotic symptoms and suffered from CO poisoning 15 years ago is presented in the light of literature findings. After CO poisoning, a close follow-up with neuropsychiatric evaluation and regular neuroimaging should be planned. The diagnosis and treatment of neuropsychiatric symptoms and disorders caused by CO poisoning, which is the leading cause of intoxication-related deaths all over the world, is important. Clinicians should be careful about medical evaluations in patients with atypical features and late-onset psychotic complaints and a history of CO poisoning.