Business IT Alignment is considered an enduring topic in academic and practitioners’ literature. The interest in the subject is justified by the link, demonstrated by several studies, between alignment and corporate performances. However, alignment research has not yet been translated into practices, theoretically demonstrated in literature and applied to companies. The interpretation of alignment as a function of independent factors and the underestimation of the complex nature of alignment process are considered key barriers in alignment achievement. The present study is based on a multi- case study analysis carried out in two companies that implemented alignment processes. We conceptualise alignment as a co-evolution process and derive four mechanisms and three types of parameters and explain their role in alignment mplementation. The contribution is theoretical, since we analyse and describe mechanisms and factors that govern alignment, and for the practitioners, since knowledge of these mechanisms is precondition for an effective alignment implementation.