The syndrome of inappropriate antidiuretic hormone (SIADH) has been describ
ed in patients suffering from leukemia or lymphoma involving the central ne
rvous system. Several alkylating agents have also been associated with this
syndrome. We describe a patient with chronic lymphocytic leukemia, without
evidence of central nervous system involvement, who suffered from SIADH pr
esumably caused by small doses of chlorambucil.