The ultrasound findings of two cases of fallopian tube duplication, both of which had undergone torsion, are described. Two premenarchal girls were examined with ultrasound because of clinical evidence of pelvic pathology. Both were found to have complex cystic structures that on surgery and subsequent pathological examination were shown to be twisted accessory fallopian tubes. Accessory fallopian tubes have been reported to occur in 6-13% of selected patient groups. To our knowledge, torsion of an accessory tube has not been reported in the literature.