We present reliable field techniques for capturing, anesthetizing, and Iidentifying individual cotton-top tamarins (Saguinus oedipus oedipus). A new technique is presented for radio-tracking small bodied primates. A backpack-style harness was designed to carry a transmitter. This system appears effective in minimizing potential injury and does not appear to interfere with the normal behavior of the animal. © 1993 Wiley-Liss, Inc.