The complement system is a first-line defence mechanism against parasi
tes. All parasites causing deep infections and getting into contact wi
th human plasma must, in one way or another, avoid the destructive eff
ect of this powerful defence system. Several specific strategies of co
mplement resistance of parasites have been reported, and this rather l
arge spectrum of regulatory mechanisms covers the whole cascade of com
plement activation. Analysis of the known and elucidation of the yet u
nknown mechanisms will probably help in the development of new therape
utic and preventive approaches to control the different parasitic dise
ases. This paper will review the complement resistance mechanisms repo
rted and their utilization by various parasites.