Introduction Military action in Ukraine led to increasing in the number of patients with PTSD among children. Open-label studies demonstrated the efficacy of SSRI’s for the treatment of PTSD, primarily paroxetine. Feasibility of using of these drugs in children and adolescents is controversial [1-2]. Objective To evaluate a short and long-term efficacy and tolerability of fluoxetine in the treatment of PTSD in children. Methods double-blind, placebo-controlled 12-week study with a fixed dose of fluoxetine (20-40 mg). The trial design consisted of 1-week, single-blind, placebo run-in period, followed by a 12-week treatment period and a 2-week taper phase. Were randomized 110 children aged from 12 to 18 years (MD = 14,2), that have been moved from the combat zone in the east of Ukraine and met the DSM-5criterias for PTSD. Drug efficacy was assessed weekly using the CAPS-2; CGI-I / CGI-S. Safety assessed: Adverse event (AE) recording, suicidality assessment. Result The reduction in CAPS-2 scales was statistically significant among children randomized to fluoxetine treatment compared with placebo in a week 12 endpoint (treatment difference -11.10; 95% Cl-13.4, -7,38; p Conclusion Fluoxetine at a dose of 20-40 mg / day is more effective than placebo, well-tolerated and can be recommended in pediatric practice.