This study investigated the frequency and distribution of canine patellar luxation (PL) in Bucheon city during January 2003 to December 2006. The 144 dogs with PL were analyzed according to grade, breeds, sex, age, body weight, and existence of concurrent cranial cruciate ligament rupture. Small breed including Yorkshire Terrier (31.65%), Maltese (33.09%) and Poodle (12.23%) had higher distribution of PL. Especially Yorkshire Terrier and Maltese had higher population of PL compared with other breeds. Most of them were diagnosed as II-III grade PL, and only a few dogs had grade I and grade IV PL. Small breed of body weight 2-3 kg (38.88%) had higher population of PL, and most of them were intact female (46.52%) and castrated male (38.19%) dogs. This study showed that clients recognized the necessity of the operation for dogs with PL well when the dogs are 6 months and 3 year-old, and have II-III grade PL. The reason that body weight of 2-3 kg had higher percentage of PL is related to the breeds. In analysis, intact female and castrated male dog had higher distribution of PL. The occurrence of concomitant cranial cruciate ligament rupture was 11%. Patellar luxation is therefore considered having an influence on cranial cruciate ligament rupture.