This thesis revolves around two controversies. The first controversy being the scientific dispute weather anti-immigrant party success should best be analyzed on basis of demand- or supply- side factors. In this thesis these two opposing perspectives are applied on the Swedish parliamentary election in 2010 to test their ability of explaining the electoral success of the Swedish anti-immigrant party “Sverigedemokraterna.” The second controversy regards the diverging scientific results on when in time the immigration- issue became an issue used by the Swedish electorate to distinguish and select among parliamentary parties. The main findings of this study is that the supply-side of the argument on what is better used to explain anti-immigrant party success is right as to say that demand is not the critical issue. However the results can also not support the assumption made by supply- side advocates that anti-immigrant party success is best understood in terms of agenda setting and issue- priming- effects. The thesis also concludes that the immigration- issue has been an issue of relevance to the Swedish electorate when distinguishing and selecting among parliamentary parties since 1991.