We studied retrospectively twenty-nine operations for removal of loose bodies from the knee under arthroscopic control from August, 1982 to Mach, 1985. We succed to remove loose bodies arthroscopically in 24 knees, but failed in 5 knees. The loose bodies were not visible radiologically in 12 knees, and more than one loose body was present in 10 knees. The loose bodies, above Smm in diameter among the removed, were forty three; their mean diameter was 7.5 mm and the most large one was 35 mm in diameter. The loose bodies were found most commonly from intercondylar notch area and the most common associated internal derangements was meniscal injury. The mean time for return to work was 2.5 weeks(range 1 to 4.5 weeks). The operation required considerable arthroscopic expertise and could be technically more exacting than other artroscopic procedures. After average two years and four months follow-up(range one year and five months to three years and eleven months), pain on knee joint was remained in five patients who had taken other associated derangement in same knee, but the patients who had loose bodies in knee joint as only problems were cured completely to normal knee joint function.