Background Three patients with late-onset infection after multilevel instrumented anterior spinal fusion for idiopathic scoliosis, using the Cotrel-Dubousset-Hopf (CDH) system, are presented. The CDH-system is an anterior instrumentation with high biomechanical stability and rigidity, ensuring a stable primary fixation. Unlike after posterior spinal fusion, infection after anterior spinal fusion (ASF) for idiopathic scoliosis has rarely been reported. Methods The files of three patients who developed an infection after ASF for scoliosis using the CDH-system, were reviewed. The clinical presentation and diagnostic and therapeutic options are discussed. Results All three patients had a late-onset infection of the CDH-system, which was difficult to diagnose because of nonspecific symptoms. Radiographs and technetium bone scan appeared to be of low value. When an abscess was present, this could accurately be diagnosed with MRI or CT imaging. Operative treatment with implant removal and antibiotic therapy was successful in all cases. Conclusion Late onset infections after ASF using the CDH-system presented with few and nonspecific symptoms. The clinical presentation was mainly characterized by vague abdominal-or back-pain after an interval of normal postoperative recovery, moderately raised infection parameters and inconclusive findings with imaging modalities. As treatment, implant removal, debridement and parenteral antibiotics are recommended. It should be noted though that implant removal poses serious risks for vascular and visceral structures.