Two patients with prior prostate surgery sustained peripheral nerve injuries after transurethral collagen injection for the treatment of urinary incontinence. In the first patient, brief lithotomy positioning caused a gluteal compartment syndrome and sciatic neuropathy. In the second patient, obturator neuropathy was due to leakage of collagen along the course of the obturator nerve. This is the first report of peripheral nerve injury in patients undergoing transurethral collagen injection.