Overactive bladder (OAB) is a common problem in modern population. The main line of medical treatment of this condition is the use of M-cholinoblockers. Solifenacin has shown high selectivity for the bladder in preclinical studies. Data on the efficacy and safety of high-dose (10 mg/day) of solifenacin are insufficient. The study was aimed to the comparative evaluation of the effectiveness and safety of solifenacin at a dose of 5 and 10 mg/day. The study included 28 patients (17 women and 11 men), mean age was 41.3±6.7 years. All patients were divided into two groups. In Group 1 included 12 patients with idiopathic overactive bladder, the Group 2 (n=16) - with neurogenic overactive bladder. Depending on the effect obtained, in some patients the dose was increased to 10 mg/day 1 month after starting treatment. The duration of treatment was 12 weeks. Application of solifenacin at a dose of 5 mg in patients with overactive bladder significantly reduces the severity of symptoms. Increasing the dose was required in 3 (25%) patients with idiopathic OAB and in 10 (62.5%) - with neurogenic OAB. Patients unsatisfied by therapy with solifenacin 5 mg/ day initially had more severe symptoms of the disease - significantly more urgency frequency, incontinence episodes, and nocturia. The use of high doses of solifenacin increased the effectiveness of treatment. Statistical significance was achieved for all parameters evaluated. Against the background of increasing doses, the number ofadverse effects may increase, but within a month of therapy in most cases they are reduced.