Somatoparaphrenia is a disorder of body perception, usually on the left side. One or both limbs are seen as foreign or as belonging to somebody else. In the literature this rare phenomenon has been described in patients with brain damage, usually due to an infarction or other lesion to the right parietal lobe. We describe a patient with schizophrenia and addiction problems who believed that his left forearm was not his, but rather belonged to a Spanish girl. An EEG and an MRI of the brain showed no abnormalities. Despite years of antipsychotic treatment, the delusion persisted. To rule out neurological causes we recommend auxiliary investigations in all patients with somatoparaphrenia. No evidence-based treatments are known for this monothematic delusion in the context of schizophrenia.