The Wolf Motor Function Test (WMFT) has been used in rehabilitation studies of chronic stroke patients, but until now its psychometric properties have not been evaluated in patients with subacute stroke. Two hundred twenty-nine participants with subacute stroke (3-9 months postinjury) at 7 research sites met inclusion criteria for the EXCITE Trial and were randomized into immediate or delayed (by 1 year) constraint-induced movement therapy treatment. All evaluations were undertaken by assessors standardized in the administration of the WMFT and masked to treatment designation. Participants were also assessed using the Fugl Meyer Motor Assessment (FMA). Delayed group members had measurements repeated 2 weeks following baseline assessment to determine learning or exposure effects. The results demonstrate that the WMFT differentiated higher from lower functioning participants across sites; scores were uninfluenced by hand dominance or affected side. Women exhibited slower performance times than men. The Functional Ability scale (FAS) portion of the WMFT also revealed lower scores among lower functioning participants and woman. Minimal changes were observed after repealing the WMFT among delayed group participants 2 weeks later. The FMA revealed similar results when the total group was divided into higher and lower functional levels at its midpoint score of 33. The WMFT discriminates higher from lower functioning participants tested across research sites. Comparable findings using the FMA support the criterion validity of the WMFT. Copyright © 2005 The American Society of Neurorehabilitation.