We present the case of a patient with classical protein C deficiency p
resenting with acute priapism during warfarinization for thrombophlebi
tis. Priapism is a well-recognized complication of a number of conditi
ons including sickle cell disease and haematological malignancies, but
to our knowledge it has not previously been reported in association w
ith protein C deficiency, This case highlights the potential dangers o
f initiating oral anticoagulant therapy using conventional loading dos
e regimens in patients with protein C deficiency.