There are concerns about percutaneous closure of patent foramen ovale (PFO) using nitinol-alloys devices in patients with nickel hypersensitivity. We describe our experience with Atriasept II (Cardia Eagan, Minnesota, USA) used in four patients with known nickel allergy. No intraprocedural or in-hospital adverse events occurred. The follow-up was negative for allergic manifestations, without complications, as assessed by echocardiography. Because of the risk of adverse outcomes in nickel-allergic patients, devices with higher biocompatibility, low-profile, and low nickel content should be preferred in cases of known hypersensitivity. Atriasept II, containing less metallic material, appears to be a safe option in allergic patients undergoing PFO closure.