The effect of glenohumeral arthritis and subsequent total shoulder arthroplasty (TSA) on shoulder proprioception has not been evaluated previously. A prospective analysis of 20 consecutive patients with unilateral advanced glenohumeral arthritis who underwent TSA was undertaken. Shoulder proprioception testing for passive position sense and detection of motion was performed 1 week before surgery and 6 months after TSA. The presence of glenohumeral arthritis had a significant effect on position sense for all 3 planes tested (flexion, abduction, and external rotation). There were significant differences (P < .05) compared with the uninvolved shoulder and with a group of 20 age- and gender-matched subjects without a history of shoulder problems. Six months after TSA, position sense was significantly improved (P < .05) and was not significantly different from that in the contralateral shoulder or the comparison group. Detection of motion was also significantly worse in the arthritic group compared with that in the uninvolved contralateral side (P < .05). Six months after TSA, the sensitivity to detection of motion improved (P < .01) and was not significantly different than that in the uninvolved contralateral shoulder. In addition, the postoperative values for the involved shoulder were not significantly different than those in the age- and gender-matched comparison group. This study demonstrates a significant decrease in proprioceptive function in patients with advanced glenohumeral arthritis. After TSA, there was a marked improvement in proprioception.