The early diagnosis of osteomyelitis of the patella in children can be difficult due to the rarity of this infection and to the vagaries of presentation which may be either acute with systemic signs or insidious with mild local signs. We present four cases of patellar osteomyelitis to illustrate the spectrum of this disorder. There should be a high index of suspicion with persistent pain and swelling above the knee, septic prepatellar bursitis, and septic knees that do not respond to conventional management. Management parallels treatment of osteomyelitis of other bones.