To examine the influence of unilateral spatial neglect (USN) on upper extremity function changes after a modified constraint-induced movement therapy (mCIMT) program. Secondary analysis of intervention data. Outpatient rehabilitation. Individuals with mild to moderate hemiparesis post stroke. mCIMT program (3 days/week, 60 minutes/day, 4 weeks). We used the line orientation subtest of the Repeatable Battery for the Assessment of Neuropyschological Status and clinical evidence of neglect to characterize USN. We used the Chedoke Arm and Hand Activity Inventory (CAHAI-9) to measure upper extremity function at baseline and 4 weeks. We compared mean baseline and week 4 upper extremity function scores of individuals who did and did not demonstrate USN at baseline (t tests for exploratory purposes; Cohen's d effect sizes). Nineteen participants (9 right hemisphere; 10 males; mean age 59) completed the program. Participants who demonstrated USN (n=6) scored lower on the CAHAI-9 at baseline than participants who did not demonstrate USN (n=13; t17=1.37, p=.19). This difference was characterized by a moderate to strong effect size (Cohen's d=.63). After therapy, there were no significant differences between groups on the CAHAI-9 (t13=.34, p=.74), this lack of difference further supported by a small effect size (Cohen's d=.16). A comparison of the magnitude of CAHAI-9 change scores between groups indicated a small to moderate effect size (Cohen's d=.39) favoring the USN group. Preliminary findings suggest that individuals with USN benefit from participation in a mCIMT program and may even benefit more (i.e. greater change scores) than individuals without USN due to the increased potential for improvement. The small sample size limits the generalizability of these findings and future research to examine the short and long term effects of mCIMT on upper extremity recovery in individuals with USN is warranted.