This article examines the single-issue party thesis for the specific case of contemporary extreme right parties (ERPs) and the immigration issue. I define the single-issue party as (l) having an electorate with no particular social structure; (2) being supported predominantly on the basis of one single issue; (3) lacking an ideological programme; and (4) addressing only one all-encompassing issue. On the basis of a comprehensive analysis of electoral studies and party literature the single-issue party thesis is rejected on all counts. At best, immigration has been a catalyst for most ERPs in certain periods of time. Their ideology and broader programe will keep ERPs in the political arena for some time to come, even in the unlikely event that immigration would cease to be an important political issue.