Background Polyalkylimide is a nonresorbable, biocompatible polymeric filler that has been used for several years to treat soft tissue deficits. The literature has shown a minor complication rate. We noticed that complications typically appear several years after injection. Objective To evaluate the complications reported after treatment with polyalkylimide. Methods and materials We describe a retrospective evaluation, reported by members and candidate members of the Dutch Society of Cosmetic Medicine, of complications after use of polyalkylimide. Results In total, 3,196 patients were treated, and 4,738 treatments were performed, from which 154 complications (patient complication rate 4.8%, treatment complication rate 3.3%) were reported. The most common complication was inflammation; other complications were hardening, migration, and accumulation of the product. In some patients, skin biopsy followed by histologic examination was performed. Conclusion Treatments with polyalkylimide have been reported to give rise to complications years after treatment. Even though the study described is a retrospective evaluation, we consider an overall complication rate of 4.8%, the severity of the complications, and the difficulty in treating them too high a risk for a cosmetic treatment. The Dutch Society of Cosmetic Medicine advises against the use of polyalkylimide.