Generalized anxiety disorder (GAD) is associated with an imbalance in the functioning of the stimulating neurotransmitter systems in human's brain. We studied the safety and therapeutic efficacy of aviandr, the new noradrenergic and specific serotonergic antidepressant, for GAD patients in the phase II, double-blind, placebo-controlled, randomized, multicenter, pilot trial at 17 clinical sites of the Russian Federation. 129 eligible patients were 18 years and older and met the criteria for GAD diagnosis. The patients were randomly assigned (1:1:1) to receive oral aviandr at daily dose of 40 mg (cohort 1, n = 41) or 60 mg (cohort 2, n = 43) or placebo (cohort 3, n = 43) for 8 weeks. The patients were assessed by the Hamilton anxiety scale (HAM-A), Hamilton Depression Scale (HAM-D), Clinical Global Impression Scale (CGI-S), Visual Analogue Scale and vital signs. At week 8, the decreases of the HAM-A score were achieved in 53∙7%, 47∙7% and 16∙3% in cohorts 1, 2 and 3, respectively. Changes of HAM-A, HAM-D, CGI-S, and CGI-I scores in aviandr-treated patients were superior to placebo (p < 0∙001). The psychic components of anxiety decreased on the first day, throughout the 8 weeks of treatment and on a follow-up week after aviandr discontinuation. Aviandr (40 mg daily dose) reduced drowsiness compared to baseline, was safe, well-tolerated and did not cause serious or severe adverse events or signs of withdrawal syndrome within one week after treatment completion. Aviandr at both 40 and 60 mg daily doses demonstrated therapeutic efficacy in GAD patients over placebo.