Background: The influence of isolated limb perfusion (ILP) on the limb recurrence-free interval (LRFI) and the number of lesions per recurrence was studied for patients with frequently recurring regional in-transit metastases previously managed by excisional surgery. Methods: All 43 patients who had their first ILP for a third or further limb recurrence were selected from our computer database of 451 patients who underwent therapeutic ILP for recurrent extremity melanoma in our centers. Eighteen patients had resectable and 25 had locally unresectable lesions at the time of ILP. The patients had a total of 269 intervals between treatment of their primary melanoma and last recurrence or last follow-up. Median follow-up was 35 months (interquartile range, 14-64 months). Results: The median LRFI decreases over time from primary melanoma to the third or further recurrence for which ILP was performed (P < 0.001). The median LRFI is 4.7 times longer (95% confidence interval [CI], 2.8-7.9; P < 0.001) after ILP in comparison with the last interval before ILP. Patients with resectable lesions have a median LRFI that is 5.9 times longer (95% CI, 2.7-13; P < 0.001). In all patients, the number of lesions increases by 22% per recurrence number (95% CI, 10%-35%; P = 0.02). At the same recurrence number, patients before ILP have a 2.6-fold higher (95% CI, 1.6-4.5) mean number of lesions than do patients after ILP (P < 0.001). Conclusions: ILP lengthens the LRFI and decreases the number of lesions per recurrence significantly in patients with repeatedly recurrent limb melanoma. Therefore, ILP could be a valuable adjunct to excisional surgery for in-transit metastases in these patients whose LRFIs tend to shorten over time.