The postmenopausal state covers 40% of modern women’s lives and 50–70% of postmenopausal women report GSM symptoms such as vaginal dryness, itching, frequent inflammations, lack of elasticity, or dyspareunia. Consequently, a safe and effective method of treatment is crucial. In a group of 125 patients, a prospective observational study was performed. The aim was to evaluate the clinical effectiveness of fractional CO2laser in the treatment of GSM symptoms using a protocol of three procedures in 6-week intervals. The vaginal pH, VHIS, VMI, FSFI, and treatment satisfaction questionnaire were used. The fractional CO2laser treatment was effective in improving all the objective forms of evaluation: vaginal pH (from 5.61 ± 0.50 at the baseline up to 4.69 ± 0.21 in the 6-week follow-up after the third procedure); VHIS (12.02 ± 1.89 at the baseline vs. 21.50 ± 1.76); VMI (21.5 ± 5.66 vs. 48.4 ± 4.46). Similar results were obtained for FSFI: 12.79 ± 5.351 vs. 24.39 ± 2.733, where 79.77% of patients were highly satisfied. Fractional CO2laser therapy increases the quality of life by having a beneficial effect on the sexual function of women with GSM symptoms. This effect is obtained by restoring the correct structure and proportions of the cellular composition of the vaginal epithelium. This positive effect was confirmed by both objective and subjective forms of evaluating GSM symptom severity.