This work introduces examples of ethnic profiling in European counter-terrorism and analyzes possible after-effects on a theoretical basis. Primary effects, which are generally considered positive, are contrasted with secondary effects and methodological breaches, for instance the over- and under-inclusion of a profile, substitution and negative effects on the social life of the targeted group. The implications are documented with examples taken from the European counter-terrorism context and discussed in relation to European legal standards. The discussion closes with a proportionality test.