BACKGROUND Failure of chemoradiotherapy (CRT) for anal squamous cell carcinoma (SCC) results in persistent or recurrent anal SCC. Treatment with salvage abdominoperineal resection (APR) can potentially achieve cure. The aims of this study are to analyze oncological and surgical outcomes of our 30-year experience with salvage APR for anal SCC after failed CRT and identify prognostic factors for overall survival (OS). METHODS All consecutive patients who underwent salvage APR between 1990 and 2016 for histologically confirmed persistent or recurrent anal SCC after failed CRT were retrospectively analyzed. RESULTS Forty-seven patients underwent salvage APR for either persistent (n = 24) or recurrent SCC (n = 23). Median OS was 47 months [95% confidence interval (CI) 10.0-84.0 months] and 5-year survival was 41.6%, which did not differ significantly between persistent or recurrent disease (p = 0.551). Increased pathological tumor size (p < 0.001) and lymph node involvement (p = 0.014) were associated with impaired hazard for OS on multivariable analysis, and irradical resection only (p = 0.001) on univariable analysis. Twenty-one patients developed local recurrence after salvage APR, of whom 8 underwent repeat salvage surgery and 13 received palliative treatment. Median OS was 9 months (95% CI 7.2-10.8 months) after repeat salvage surgery and 4 months (95% CI 2.8-5.1 months) following palliative treatment (p = 0.055). CONCLUSIONS Salvage APR for anal SCC after failed CRT resulted in adequate survival, with 5-year survival of 41.6%. Negative prognostic factors for survival were increased tumor size, lymph node involvement, and irradical resection. Patients with recurrent anal SCC after salvage APR had poor prognosis, irrespective of performance of repeat salvage surgery, which never resulted in cure.