[Purpose] The purpose of this study was to compare the effects of action observation training and motor imagery training on recovery from chronic stroke. [Subjects] Thirty patients (who were over six months post stroke) participated in this study and were randomly allocated to three groups. [Methods] The action observation training group practiced additional action observation training for five 30-minute sessions over a four-week period. The motor imagery training group practiced additional motor imagery training for five 30-minute sessions over a four-week period. Electroencephalogram were used to compare brain waves between the three groups. [Results] The action observation group showed significant changes in relative alpha power in Fp1 and Fp2 and relative beta power in Fp2 and C3. [Conclusion] Action observation induces higher levels of cognitive activities than motor imagery and physical training. Action observation is expected to be more effective for stroke patients.