OBJECTIVES: There has been increased attention to the antipsychotic treatment of negative symptoms in schizophrenia and the potential impact that this could have on various functional outcomes.  We compared the relative effects of negative symptoms on functioning as compared to other symptoms.  METHODS: Data are from 18 months of the National Institute of Mental Health (NIMH) CATIE trial of chronic schizophrenia (n=1447).  Measures were the Positive and Negative Syndrome Scale (PANSS), functioning from the Heinrich’s (Instrumental role, Common place objects and activities) and items from the Lehman Quality of Life Scales (Leisure activities, Instrumental activities of daily living).  Quality of life items measuring negative symptoms were excluded.  Correlations between the five PANSS factors and the functional measures were examined at baseline and change.  Functioning items were summed to create a standardized total score.  Multiple regression was used to predict the functioning total score at baseline using the five PANSS factors and change in functioning using change on the PANSS factors.  RESULTS: The negative symptom factor correlated more strongly than other symptom factors with functioning at baseline and change scores.  Multiple regression predicting functioning at baseline including all five PANSS factors showed that the negative symptom factor was the strongest predictor, almost three times that of positive symptoms (r=-0.25 vs. r=-0.07).  A similar multiple regression predicting change in total functioning with change on PANSS also found that the negative factor was the best predictor and was double that of the positive factor (r=-0.08 vs. r=-0.045).  CONCLUSIONS: Baseline and change in functioning were more strongly related to the PANSS negative factor than the other four PANSS factors.  Since we focused on negative symptoms we chose domains of functioning that did not overlap with negative symptoms.  The results suggest that functioning and improvement in functioning are more strongly correlated with negative than with positive and other symptom factors.