Negative symptoms in schizophrenia are critical to functional outcomes but remain difficult to assess reliably. The Brief Negative Symptom Scale (BNSS) was developed to address these challenges, though no validation exists in Romanian-speaking populations. To validate the BNSS in a Romanian clinical sample, explore its psychometric properties and compare BNSS-based and PANSS-based classifications of severe negative symptoms. Forty-seven inpatients with schizophrenia were assessed using Romanian versions of the BNSS, PANSS, CDSS and AIMS. Psychometric analyses included internal consistency, inter-rater reliability, factor analysis and correlation-based validity. Two classification schemes, moderate–severe negative symptoms, measured by BNSS (BNSS-MS), and predominant negative symptoms, measured by PANSS (PANSS-PNS), were compared. The BNSS showed excellent internal consistency (α = .94) and inter-rater reliability (ICC = .98). A five-factor structure was confirmed. BNSS total scores correlated strongly with PANSS negative (ρ = .90), but not with positive, depressive, or motor symptoms. Blunted affect emerged as the most prominent subscale. The BNSS-MS group captured more severe cases than PANSS-PNS and showed greater symptom burden and higher distress scores. The Romanian BNSS is valid and sensitive for detecting negative symptoms, outperforming PANSS in identifying clinically significant subgroups.