Aspiration of the synovial joints is an important part of the diagnostic and therapeutic armamentarium of the physician and may provide vital information that can be obtained in no other way. As with any other technique in medicine, skill and safety in the aspiration of joints can be acquired only through careful study and continued practice in arthrocentesis. When appropriate preparations and precautions are observed, obtaining fluid from synovial joints is safe, relatively pain free, inexpensive, and extremely beneficial to the patient.