OBJECTIVES: To correlate changes in negative symptoms of schizophrenia, assessed by scores on the 16-item Negative Symptom Assessment scale (NSA-16), with changes in scores on various functional outcome scales. METHODS: Of 166 stable outpatients with schizophrenia or schizoaffective disorder participating in 1 of 3 medication or psychosocial intervention studies, 99 had data at baseline and 9 months, and were included in the analysis. The rating instruments used were the NSA-16, Brief Psychiatric Rating Scale, and several functional outcome rating scales: Quality of Life Scale (QLS), Multnomah Community Ability Scale (MCAS), Global Assessment of Functioning (GAF), Social and Occupational Functioning Assessment Scale (SOFAS), Frontal Systems Behavioral Scale (FrSBe), Functional Needs Assessment (FNA), and Life Skills Profile (LSP). The association between change scores was assessed using Pearson's correlation coefficients. RESULTS: Changes in negative symptoms showed moderate to fairly strong correlations with changes recorded on all functional outcome rating scales. The associations were statistically significant for all functional outcome measures, including structured assessments (QLS: r= –0.423, P<0.0001; MCAS: r= –0.338, P=0.0008), global assessments (GAF: r= –0.521, P<0.0001; SOFAS: r= –0.497, P<0.0001), performance-based assessments (FrSBe: r=0.414, P=0.0003; FNA: r= –0.231, P=0.0247); and observational assessment (LSP: r= –0.367, P=0.0003). This pattern of association between reductions in negative symptoms and improvements in functional outcome ratings was evident even after controlling for the effects of treatment-related improvements in positive symptoms. CONCLUSIONS: Reductions in negative symptoms, as rated with the NSA-16, are associated with improvements in clinician- and patient-assessed functional outcomes measures. This association is particularly strong when functional outcome is measured on the QLS, GAF, and SOFAS. These findings suggest that treatments that decrease negative symptoms may reduce the considerable functional disability associated with schizophrenia.