Since 1970s, the Belgian party system was transforming from national to the regional. One of the consequences is the “regionalization” of the electoral behavior. The voting patterns of Flemish electorate drift apart from their Walloon counterpart starting the 1970s but especially since 1990s. The models presented in the academic literature are focusing on cleavage based models of voting behavior. Literature review prompts our expectations of the declining partisan alignment in Belgium due to several developments in society from 1970s. We believe, however, that the pattern of this change has been non-uniform in Belgium, as the change has mainly occurred in Flanders in comparison to Wallonia. For instance, in the Walloon region, voters’ volatility is substantially lower than in Flanders and the socialist party is still the winning party since the 1970s. One would expect a growing volatility in Flanders due to the transformation of the working class; however, sociological transformations of the society do not explain the “survival” of the socialist party in the South. The paper is modeling the political behavior in one of the two main regions (Wallonia) and from 1990 to 2007 and focuses on the differences in cleavage politics in Wallonia. By using the data produced by the Belgian National Election Study (BNES), we examine the structure of cleavage system in Wallonia and evaluate parties’ alignment along the cleavage lines.