To evaluate the effects of transfer of the trapezius and/or latissimus dorsi with the teres major for treatment of dysfunction of the shoulder in obstetrical brachial plexus palsy (OBPP), 34 patients with paresis of the abductors and external rotators, as well as co-contraction of the adductors in abduction, who had undergone reconstructive operations, were followed-up for at least 1 year. Of these, transfer of the latissimus dorsi with attached teres major to the insertion of the infraspinatus (single procedure), was performed in 25 cases, and transfer of both latissimus dorsi with teres major and trapezius (to the humerus) in nine (combined procedure). Gilbert's grading system was used for evaluation. The results showed that in spite of improvement of external rotation in most of the cases, abduction was improved in only 13 of the 25 cases with a single procedure, and that eight of nine cases with a combined procedure gained improvement of both external rotation and abduction. These results indicated that, for improvement of both abduction and external rotation of the shoulder in OBPP, transfer of the latissimus dorsi with the teres major can be performed only when abduction is > or =90 degrees; otherwise, transfer of the trapezius should be added.