Introduction: In recent decades, the prevalence of focal segmental glomerulosclerosis (FSGS) has increased globally, becoming a significant cause of nephrotic syndrome. While rituximab (RTX) has been proven effective in treating pediatric FSGS, its administration in adults requires further evidence. Objectives: We studied the administration of RTX in adult-onset FSGS both steroid-dependent (SD) and steroid-resistant (SR). Patients and Methods:We conducted a single-centre retrospective, observational study from January 2018 to December 2023. Patients aged over 18 years with primary FSGS both steroid-dependent and steroid-resistant treated with rituximab were included in this study.  The RTX dose used was either 500 mg or 1000 mg. Results: This study included 12 adult patients with biopsy-confirmed primary FSGS, with an equal gender distribution and a mean age of 36.8 ± 9.21 years. Of these, 6 (50%) were steroid-dependent, and 6 (50%) were steroid-resistant. The overall remission rate (partial remission+complete remission) at 3, 6, and 12 months was 75%, 66.7%, and 58.4%, respectively. Renal function remained stable in patients who responded to therapy. The first relapse occurred at 16 months and 6 months in steroid-dependent and steroid-resistant patients, respectively, following RTX administration. During follow-up, all three steroid-resistant patients who did not respond to RTX developed end-stage renal disease, with one death. Conclusion: Rituximab was effective in treating adult steroid-dependent FSGS and may also be beneficial in steroid-resistant FSGS. However, further prospective research is needed to determine the role of RTX dosing and retreatment strategies in both steroid-dependent and steroid-resistant FSGS.