Objectives: To investigate the correlationsbetween forkhead box D1 (FOXD1) expressionand clinicopathological characteristics of bladdercancer and influence on the biological behaviors ofbladder cancer cells. Methods: The overall survival rate of 87 bladdercancer patients was evaluated to explore the predictivevalue of FOXD1. The expressions of FOXD1 in 87 bladdercancer tissues and 26 adjacent tissues were measuredthrough immunohistochemistry, and the correlationsbetween FOXD1 expression and clinicopathologicalcharacteristics of patients were analyzed. FOXD1 mimicand FOXD1 siRNA were mixed and transferred intoT24 cells to construct FOXD overexpression and knockdowncell lines. Cell counting kit-8, wound-healing andTranswell migration assays were performed to detectcell proliferation, migration and invasion. RESULTS: Prediction using bioinformatics websiteshowed that FOXD1 was highly expressed inbladder cancer tissues. The overall survival rate wassignificantly lower in bladder cancer patients withhigh FOXD1 expression than that in those with lowexpression (Psignificantly higher in bladder cancer tissues thanthat in adjacent tissues. The expression of FOXD1in bladder cancer tissues had no significant differencesamong patients with different gender, agesand tumor sizes, but significant differences amongthose with different tumor numbers, clinical stagesand histological grades (PNC group, the proliferation, migration and invasionof bladder cancer cells were significantly promotedin FOXD1 group and suppressed in si-FOXD1group (PCONCLUSIONS: FOXD1 is highly expressed in bladdercancer tissues and cells, being closely associatedwith the development and progression of bladder cancer.It facilitates the proliferation, migration and invasionof cells and carcinogenesis. FOXD1 may be a newtarget for bladder cancer therapy.