OBJECTIVE To examine the clinical outcomes of arthroscopic lunate excisions for advanced Kienböck's disease. METHODS Fifteen patients (six men and nine women; mean age: 65 years; range: 48-83 years) with advanced Kienböck's disease, who underwent arthroscopic lunate resection between April 2008 and March 2016, were reviewed clinically and radiographically after a follow-up of >2 years (mean: 29 months; range: 24-60 months). Clinical parameters, such as wrist range of motion, grip strength, Disabilities of the Arm, Shoulder, and Hand (DASH) score, and patient-rated wrist evaluation (PRWE) score were evaluated. Radiographic parameters included radioscaphoid angle, scaphocapitate angle, carpal height ratio, ulnar-triquetrum distance, and the scaphoid-triquetrum distance. Wilcoxon's signed-rank test was used to compare measurement results. RESULTS During the final follow-up, patients exhibited significant improvements, such as 42.9° in wrist range of motion (P = .009), 24.5% of the contralateral side in grip strength (P = .001), 26.2 points in DASH score (P = .002), and 37.8 points in PRWE score (P < .001), compared with the preoperative values. The radioscaphoid and scaphocapitate angles significantly increased by 4.8° (P = .0027) and 3.7° (P = .0012), respectively. The carpal height ratio, ulnar-triquetrum distance, and scaphoid-triquetrum distance significantly decreased by 0.05 (P < .001), 2.6 mm (P < .001), and 1.3 mm (P = .0012), respectively. CONCLUSIONS Our results suggest that arthroscopic lunate excisions provided excellent postoperative pain relief and functional recovery within 2 years of follow-up. Changes in carpal alignment and stress concentration on the radial side of the carpal bones could occur in the long term; however, arthroscopic lunate excision can be a good surgical option for treating low-demand patients with advanced Kienböck's disease. METHODS Level IV, therapeutic case series.