Objective To explore the value of fascial tail sign at MR images in the detection of nodular fasciitis (NF). Methods A retrospective analysis of MR images was performed in 19 patients with pathologically proven NF of the soft tissue and 53 patients with a variety of other fibrous-predominant tumors. MR manifestations of all cases were reviewed by two experienced musculoskeletal radiologists using a single blind method. The presence of fascial tail on MR images were evaluated. ROC was used to assess the value of fascial tail sign in the detection of NF. Sensitivity, specificity, Youden index and area under ROC curve were calculated. The association between the presence of fascial tail sign on MRI and pathological classification of NF was analyzed by Pearson chi-square test for independence . Results Fascial tail was present in 17 cases (89.5%) of the study group and in 6 cases (11.3%) of the control group, respectively, yielding a sensitivity of 89.5%, a specificity of 88.7%, a Youden index of 0.782 and an area under ROC curve of 0.891. The fascial tail sign was significantly associated with NF (c2=39.294,P<0.05,r=0.594). Conclusions Fascial tail sign at MRI is a moderately specific and sensitive for the diagnosis of NF relative to fibrous-predominant tumors. It can be used in differentiate between NF and aggressive soft tissue tumors.