Belantamab-mafodotin (belamaf) is a novel antibody-drug conjugate targeting B-cell maturation antigen that showed anti-myeloma activity in patients with relapsed and refractory multiple myeloma (RRMM). We performed an observational, retrospective, and multicenter study aimed to assess the efficacy and safety of single-agent belamaf in 156 Spanish patients with RRMM. The median number of prior therapy lines was 5 (range, 1-10), and 88% of patients were triple-class refractory. Median follow-up was 10.9 months (range, 1-28.6). The overall response rate was 41.8% (≥CR 13.5%, VGPR 9%, PR 17.3%, MR 2%). The median progression-free survival was 3.61 months (95% CI, 2.1-5.1) and 14.47 months (95% CI, 7.91-21.04) in patients achieving at least MR ( < 0.001). Median overall survival in the entire cohort and in patients with MR or better was 11.05 months (95% CI, 8.7-13.3) and 23.35 (NA-NA) months, respectively ( < 0.001). Corneal events (87.9%; grade ≥ 3, 33.7%) were the most commonly adverse events, while thrombocytopenia and infections occurred in 15.4% and 15% of patients, respectively. Two (1.3%) patients discontinued treatment permanently due to ocular toxicity. Belamaf showed a noticeably anti-myeloma activity in this real-life series of patients, particularly among those achieving MR or better. The safety profile was manageable and consistent with prior studies.