The antiphospholipid or Hughes' syndrome is the association between antipho
spholipid antibodies, recurrent venous and arterial thromboses and recurren
t fetal loss. There are many clinical manifestations arising from this acqu
ired thrombophilia and these are described in the article. The pathogenic m
echanism by which the antibodies cause thrombosis is the subject of much de
bate, and current theories are described. The diagnosis and management of p
atients with the syndrome are also discussed.