Purpose: To present the outcomes of treatment of Kienbock's Disease (KD) stage III, by excisional arthroplasty of lunate with Palmaris Longus (PL) tendon as a spacer. Methods: Twenty-one patients were diagnosed with KD stage III, 14 females, and 7 males. They were treated by excision of the lunate plus PL tendon ball as a spacer. Mean follow up period was 38 months (24-60). Pre- and post-operative treatment assessment were by recording the clinical examination data, the investigation by radiological imaging (plain and CT scan), MRI, and scoring of Disabilities of Arm, Shoulder and Hand (DASH) system. Results: Nineteen patients improved clinically to a great extent, by relieving symptoms, a better range of movement, functional satisfaction and no conspicuous Carpal Height Ratio (CHR) change. Mean DASH score improved from 38.5 to 6.8. Two patients had less favorable clinical outcome, yet, they were not interested to have further operations. Conclusions: Treatment of KD stage III by excisional arthroplasty plus palmaris longus tendon spacer is a low demand operation, which can be performed in a moderate hospital environment, and can accomplish good satisfactory results comparable to other more sophisticated, costly procedures. Type of study/Level of evidence: Prospective case series, level IV.