Histologic examination confirms the nonsynovial nature of cysts of the wrist, generally located on the dorsal surface. There is found a mucoid degeneration of the capsule and surrounding tissue with numerous neighboring microcysts. This is why it is irrational and usually ineffective to treat these cysts by crushing, aspiration or simple excision. These three methods result in frequent recurrences. One hundred and eighty cases were operated by excision of the cyst and all the neighboring involved tissue including in particular a disk 2 to 4 cm in diameter from the capsule of the joint. Almost all were cured, except for 3 recurrences, and any stiffness or weakness found was present preoperatively. A very detailed radiologic study (an average of 9 films per patient) made 3 years or more after operation showed there was no resultant carpal instability. In spite of its radial character this is the operation of choice in view of its efficacy and in cases where treatment is justified because of appearance or interference with function.