A total of 61 patients with gastro-oesophageal reflux; resistant to medical therapy, were entered into a prospective randomized trial comparing the Angelchik antireflux prosthesis with Nissen's fundoplication. Both groups had a similar age and sex distribution and their reflux profiles were comparable. An Angelchik prosthesis was inserted in 30 patients and 31 underwent fundoplication. The mean duration of postoperative follow-up was 38 months. At clinical assessment 23 (77 per cent) of the Angelchik group were graded Visick grade I or II, compared with 29 (94 per cent) of the Nissen group. Assessment by 24 h pH monitoring and manometry between 3 and 6 months after operation showed that both procedures were equally effective in reducing reflux and increasing lower oesophageal sphincter pressure. However, long-term endoscopic follow-up revealed grade III oesophagitis in seven patients in the Angelchik group. No patient in the fundoplication group had grade III oesophagitis. Three of eight patients with strictures in the Angelchik group reported persistent dysphagia. All seven patients with strictures in the Nissen group were relieved of their dysphagia. Migration or erosion of the prosthesis did not occur. Three prostheses (10 per cent) were removed, two for dysphagia and one because of sepsis.