The use of ligation intersphincteric fistula tract in combination with mucosal advancement flap are relatively easy procedure, which is safe and effective at the same time. It can be ideal for treating complex perianal fistulas in patient with no previous intervention. Objectives: To evaluate effectiveness of combined ligation of intersphenictreic fistula tract (LIFT) and mucosal flap advancement in treatment of complex perianal fistula. Methods: This is a prospective study of patient underwent combined ligation intersphenictreic fistula tract and mucosal flap advancement in treatment of complex perianal fistula in Zagazig University hospital during the period from July 2019 to December 2021 on 24 patients with a diagnosis of complex fistula-in-ano.High fistulas (19),Branched fistula (3),and two anterior fistulas in females. Results: Post operative wound infection occurred in three patients 12.5% drainage of seroma was done and proper antibiotic according to culture and sensitivity. one of them the infection subcide completely with complete healing and the other two patients develop recurrent fistula one in the same site of original fistula site ,the other is 2cm from original fistula site. Recurrence after surgery and Incontinence to flatus only occurred in 8.3% of cases, 4.2 % of the studied patients respectively. Conclusion: Using The combination of ligation of the intersphincteric fistula tract &mucosal advancement flap can be used in treatment of complex anal fistula with promising results and minimal affection on anal sphincter & continence