It is known that complete axillary lymph node dissection for breast cancer treatment causes more frequent sensitive and motor alterations in the homolateral shoulder and upper limb than sentinel lymph node (SLN) biopsy. However, it is not clear how often patients treated by SLN biopsy suffer from shoulder mobility (SM) restriction, as well as its severity and duration. This study was done aiming to evaluate SM in 38 patients with early infiltrating breast cancer treated by SLN biopsy in whom shoulder movements were assessed before surgery and repeated at one, two and three months later. Shoulder-arm mobility was evaluated by goniometry considering flexion, abduction, aduction, extension, internal rotation and external rotation. An abnormal result for each movement was defined by restriction greater than ten degrees compared to preoperative findings. Significant abnormal results for flexion and abduction were found in all of the patients at the first month evaluation. At the third month assessment no women showed any kind of SM impairment. The average restriction evolution for each of the parameters is presented. It is concluded that there is frequently a slight and transient SM limitation in patients undergoing SLN biopsy. Early postoperative physiotherapeutical assistance should thus be advisable to relieve and shorten disability symptomatology.