Teclistamab is a BCMA/ CD3 bispecific T cell engager, FDA approved in relapsed/refractory multiple myeloma (RRMM) after 4 prior lines of therapy, based on the results of MajesTEC-1 study. Early toxicities of teclistamab include CRS and ICANS. To mitigate the risk of CRS/ICANS, teclistamab is administered in a step-up dosing approach. 48h inpatient observation after each of the 3 step-up doses is recommended, although not mandated by FDA. Based on our outpatient CAR-T program experience, we implemented an outpatient teclistamab step-up dosing administration program. To evaluate safety of outpatient teclistamab administration. Retrospective review of toxicity outcomes of patients treated in outpatient teclistamab program at Fox Chase. Comprehensive Cancer Center, BMT program. Eligible patients were required to stay within 1h from Fox Chase with a caregiver during the observation period (days 1-10). Patients and caregivers received education on CRS and ICANS. Teclistamab was administered on days 1, 3, and 8. Safety monitoring protocol included daily evaluation in the outpatient clinic, home monitoring of vital signs, and 8 pm physician phone call on days 1-5 and 8-10, within 48h window after each step-up dose. CBC, CMP, CRP, ferritin were monitored at each visit. Patients with CRS/ ICANS of any grade were admitted for observation and management. Between 12/2022-5/2023, 18 patients completed outpatient teclistamab step-up dosing. The median age was 66y (46-81). 12(66.7%) patients did not have CRS/ICANS. 5(27.8%) patients had grade 1 CRS, of which 1(5.6%) had concurrent grade 1 ICANS. 1(5.6%) patient had grade 2 CRS. Of the 6 CRS events, 3(50%) occurred after the first dose and 3(50%) after the second dose. 5 of 6 patients with CRS received 1 dose of tocilizumab, and the patient with concurrent ICANS also received dexamethasone, with prompt resolution of symptoms. All patients completed step-up dosing with no recurrent CRS/ICANS. Outpatient teclistamab step-up dosing administration with close monitoring and prompt hospitalization for toxicity management is safe and feasible in heavily pre-treated RRMM patients. This approach allows a significant reduction of inpatient stay, resulting in significant healthcare resource savings and improvement of patients’ experience.