Purpose To outline the MR imaging and classifications of complex female genital tract anomalies in pediatric patients.Materials and methods The MR imaging of twenty one pediatric patients with this condition was reviewed and analyzed.Results Genital tract anomalies with obstruction and those involved more than one organ of female genital tract or associated with extragenital anomalies were included as complex female genital tract anomalies.Based on the MR imaging and related embryology,they could be classified as follows: one case of unicornuate uterus with absence of contralateral kidney,ovary and fallopian tube(hypoplasia of a urogenital ridge); three case of Mayer-Rokitansiky-Kuster-Hauser syndrome(total or partial agenesis of both mullerian duct),of which one was complicated with ipsilateral kidney agenesis and rectum fistula; five cases of Herlyn-Werner-Wunderlich syndrome(four typical and one atypical); four lower vagina atresia; and eight cases of vaginal or cervico-vaginal agenesis with functional uterus,of which the uterus was normal in one case,septate in one,unicornuate in four and didelphys in four.Of the twenty one patients,eighteen were obstructive and three were non-obstructive(with no obstruction or non-functional uterus); nine cases were complicated with extragenital anomalies.Conclusion The classification of complex female genital tract anomalies can be difficult since the underlying embryology is still controversial.MR imaging,with its advantages,is the imaging modality of choice to assess the complexity of this condition,guiding proper treatment.