The problem of this study is to determine the vitamin B-6 status of patients who have chronic obstructive pulmonary disease (COPD). Erythrocyte aspartate transaminase assay was the method for measuring vitamin B-6 status. The vitamin B-6 status was examined in thirty subjects (ten COPD subjects and twenty control subjects). An unpaired t-test was used to compare the vitamin B-6 status of the COPD group versus the control group. Four determinants (percentage stimulation, ratio of basal to stimulated activity, basal activity, and stimulated activity) were used to determine vitamin B-6 status in both groups of subjects. Percentage stimulation and ratio of basal to stimulated activity were not significantly different (control group versus COPD group) at the .05 level. However, two of ten COPD subjects had values for percentage stimulation that were two standard deviations above the mean, indicating a poor B-6 status. In contrast, basal activity and stimulated activity of erythrocyte aspartate transaminase were found to be significantly lower at the .05 level in the COPD group than the control group. Therefore, the COPD subjects as a group had some biochemical characteristics of a lower level of vitamin B-6 than the controls.