Historically there have been many discussions about the effect of patellectomy on the knee functions. Currently many authors agree that patellectomy decreases the knee function in many ways. Authors conducted a clinical study on the effect of patellectomy in 11 patients (7 males and 4 females) who underwent total or partial patellectomy from Jan 1980 to June 1987. The mean age at surgery was 44 years, and the mean follow-up period was 8 years 3 months ranging from 3 years 4 months to 10 years 2 months. 5 patients underwent total patellectomy, and 6 patients underwent partial patellectomy. The indications of surgery were comminuted patellar fracture in 9 cases, severe chondromalacia in one case, and chondroblastoma of patella in one case. The results are as follows;1. Good to excellent results were obtained in 8 cases (72.7%) and fair results in 3 cases (27.3%). Among total patellectomy cases good to excellent results in 3 cases (60.0%), and fair results in 2 cases (40.0%). Among partial patellectomy cases, good to excellent results in 5 cases (83.3%), and fair result in 1 case (16.7%). 2. Pain and limitation of activity were interrelated with degenerative radiologic changes.