OBJECTIVE To demonstrate the cause of and optimal treatment for recurrent trigeminal neuralgia (TN) in cases where veins were observed to be the offending vessels during the initial microvascular decompression (MVD) procedure. METHODS An electronic search of patient records from 1988 to 1998 revealed that 393 patients were treated with MVD for TN caused by veins. The pain recurred in 122 patients (31.0%). Thirty-two (26.2%) of these patients underwent reoperations. Clinical presentations, recurrence intervals, surgical findings, and clinical outcomes were analyzed. RESULTS Analysis of 32 consecutive cases of recurrent TN initially attributable to veins revealed a female predominance (female/male = 26:5), with one female patient exhibiting bilateral TN caused by venous compression. Patient ages ranged from 15 to 80 years, with a prevalence in the seventh decade. The V2 distribution of the face was involved more frequently than other divisions. For 24 patients (75%), recurrence occurred within 1 year after the initial operation. At the time of the second MVD procedure, development of new veins around the nerve root was observed in 28 cases (87.5%). After successful subsequent MVD procedures, the pain was improved in 81.3% of the cases. CONCLUSIONS The recurrence rate for TN attributable to veins is high. If pain recurs, it is likely to recur within 1 year after the initial operation. The most common cause of recurrence is the development and regrowth of new veins. Even fine new veins may cause pain recurrence; these veins may be located beneath the felt near the root entry zone or distally, near Meckel's cave. Because of the variable locations of vein recurrence, every effort must be made to identify recollateralized veins. Given the high rate of pain relief after a second operation, MVD remains the optimal treatment for the recurrence of TN attributable to vein regrowth.