Aim The medico‐surgical strategy for the treatment of perianal fistulizing Crohn's disease (CD) following surgical drainage remains challenging and debated. Our aims were to describe the failure rate of therapeutic interventions after drainage of the fistula tract and determine the factors associated with failure to optimize medico‐surgical strategies. Method All consecutive patients with perianal fistulizing CD who underwent surgical drainage with at least a 12‐week follow‐up were included. Failure was defined as the occurrence of at least one of the following items: abscess recurrence, purulent discharge from the tract, visible external opening and further drainage procedure(s). Results One hundred and sixty‐nine patients were included. The median follow‐up was 4.0 years. The cumulative failure rates were 20%, 30% and 36% at 1, 3 and 5 years, respectively. The cumulative failure rates in patients who had sphincter‐sparing surgeries or seton removal were significantly higher than in those who had a fistulotomy. Anterior fistula [hazard ratio (HR) = 2.52 (1.13–5.61), P = 0.024], supralevator extension [HR = 20.78 (3.38–127.80), P = 0.001] and the absence or discontinuation of immunosuppressants after anal drainage [HR = 3.74 (1.11–12.5), P = 0.032] were significantly associated with failure in the multivariate analysis model. Conclusion Combined strategies for perianal fistulizing CD lead to a failure rate of 36% at 5 years. Where advisable, fistulotomy may be preferred because it has a lower rate of recurrence. The benefits of immunosuppressants require a dedicated prospective randomized trial.