‎ Background: Painful flexible flat foot is a common pediatric foot problem result in ‎longstanding arthritic changes in subtalar joint complex. Use of subtalar arthroereisis screw ‎can prevent excess calcaneal eversion and restore normal subtalar biomechanics. Methods: ‎Thirty feet in 15 patients with symptomatic flexible flat feet between 5-12 years (11males and ‎‎4 females). Subtalar arthroereisis screw was used in all cases through direct lateral mini-sinus ‎tarsi incision. We used the AOFAS and VAS for clinical evaluations. The talo-calcaneal angle, ‎Meary's angel, calcaneal valgus angle and calcaneal pitch angle were used for radiological ‎evaluations. Results: Thirty feet were followed up for 18 months, preoperative pain was ‎improved from 3.29 ± 1.49 to 0.45 ± 0.49 postoperative according to the Visual analogue ‎scale (VAS) also the American orthopedic foot and ankle score (AOFAS) was improved from ‎‎70.87 ± 2.69 to 95.4 ± 3.55 postoperative. Postoperative complications: one foot with screw ‎subluxation after 4 weeks and one foot with superficial infection treated with proper ‎antibiotics. Conclusion: Subtalar arthroereisis screw is a mini-invasive procedure effective in ‎treating symptomatic flexible flat foot with correction of heel valgus and restoration of the foot ‎arch. ‎