Othello syndrome (OS) is a type of delusional jealousy, characterized by the false absolute certainty of the infidelity of a partner. This syndrome is not uncommon in Parkinson's Disease (PD), appearing as side effect of Dopaminergic Agonists (DA) therapy. We analyze the observations of five patients with OS, diagnosed in a series of 250 consecutive PD patients during two years. All patients are men, with a particularly young age at onset of PD. The mean duration of DA therapy at OS onset was 3 years. One patient had hypersexuality and another had punding. Significant cognitive impairment was present in two patients. All patients were treated with DA: two with Pramipexol and three with Piribedil. At the time of the management of the OS, three patients had already divorced their spouse. It is imperative for clinicians to know this underestimated syndrome in order to identify it early and approach it adequately to avoid irreversible negative prejudice.