Background: Intranasal sprays are recommended as targeted therapy for allergic rhinitis (AR). Triamcinolone acetonide is a nasal corticosteroid preparation indicated for the treatment of seasonal and perennial AR (PAR) in different countries worldwide. Objectives: In order to determine the efficacy of triamcinolone acetonide in the treatment of PAR, the non-inferiority of triamcinolone acetonide to fluticasone propionate was assessed in Russian adults. Methods: In this randomized, double-blind, parallel-group, multicenter, prospective, non-inferiority, phase III clinical trial, a total of 260 patients with persistent PAR were randomized to receive either triamcinolone acetonide or fluticasone propionate nasal sprays for 4 weeks. The efficacy in symptom control was evaluated using the reflective total nasal symptom score (rTNSS) from baseline (day 0) to day 28. Safety was assessed through the reporting of adverse events. Results: The rTNSS mean values decreased from baseline to the end of study treatment (day 28) in both groups: –8.2 ± 3.0 in the triamcinolone acetonide arm versus –8.0 ± 2.8 in the fluticasone propionate arm. The mean difference between the groups (triamcinolone acetonide – fluticasone propionate) for rTNSS change from baseline was –0.2 (95% confidence interval –0.89 to 0.54), with an upper confidence limit of 0.54, which is lower than the non-inferiority margin of 0.8. Triamcinolone acetonide was well tolerated, with no difference in adverse event occurrence compared with fluticasone propionate. Conclusions: Triamcinolone acetonide proved to be non-inferior to fluticasone propionate in adult patients with PAR; both treatments decreased rTNSS values and showed a good safety profile.