Introduction: The study aims to compare the efficacy and safety of bulking agents and single-incision slings in the treatment of urinary incontinence in 159 patients during a 29-month follow-up period. Material and methods: Of the 159 patients suffering from stress urinary incontinence, 64 were treated with bulking agents (PAHG Bulkamid®) and 75 with a single-incision sling (Altis®). The ICIQ-UI-SF (Incontinence Questionnaire-Urine Incontinence-Short Form), PISQ-12 (Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaires short form), FSFI (Female Sexual Function Index), FSDS (Female Sexual Distress Scale), and PGI-I (Patient Global Improvement Index) were used to assess efficiency and quality of life. Results: The bulking agents showed high efficacy and safety during the 29-month follow-up. Post-operative complications were recorded in both groups, with only two significant differences. The Bulkamid group experienced no pain, while 10.8% of the ALTIS group experienced groin pain and 5% experienced de novo urgency. Furthermore, patients treated with bulking agents experienced reduced nicturia (0.78 vs. 0.92 in patients treated with single-incision slings.). In both groups, we noticed a significant improvement in QoL (quality of life), with a halved ICIQ-UI-SF (International Consultation on Incontinence Questionnaire-Urine Incontinence-Short Form) score which was completed to assess the impact of urine symptoms. After 24 months of therapy, the Bulkamid group saw a decrease from 14.58 ± 5.11 at baseline to 5.67 ± 1.90 (p < 0.0001), whereas the ALTIS group experience a decrease from 13.75 ± 5.89 to 5.83 ± 1.78. Similarly, we observed an improvement in sexual function, with the number of sexually active patients increasing from 29 to 44 (56.4%) in the Bulkamid group (p = 0.041) and from 31 to 51 (61.7%) in the ALTIS group (p = 0.034). According to the most recent statistics, the PISQ-12, FSFI, and FSDS scores all demonstrated an improvement in women’s sexual function. Conclusions: In terms of efficacy and safety, bulking agents had notable results over the 29-month follow-up period. Furthermore, the patients treated with bulking agents reported a lower incidence of postoperative complications and a no discernible difference in terms of quality of life and sexual activity compared to the ones treated with single-incision slings. Bulking agents can be considered a very reliable therapeutic option based on accurate patient selection.