Purpose This paper aims to explain how small- and medium-sized firms (SMEs) create information technology (IT) business value through blended IT outsourcing (ITO). The explanatory framework it proposes enables SMEs to replicate IT capability outcomes (i.e. enhance their economic, strategic and technological competences, namely, ITO success) by endorsing an ITO strategy catalyzed by IT vendor integration. Design/methodology/approach This study uses covariance-based structural equation modeling to test the proposed research model. Data are collected from 251 knowledge-intensive business SMEs located in Science and Technology Parks in Spain. Findings The results demonstrate empirically that SMEs can replicate IT capability benefits (i.e. enhance their non-IT competences) through blended ITO in which IT, conceptualized as a transversal supporting activity, is outsourced to an IT vendor while the value creation process remains with the buyer. The integration (i.e. process integration and information sharing) of an IT-proficient vendor catalyzes ITO success. More specifically, the results show that, although process integration is not directly related to competence enhancement, fosters information sharing, which directly facilitates ITO success. The results also show that IT vendor proficiency accounts for ex ante trust. Practical implications Managers should think of transformational ITO as a strategy to enhance firm competences. For blended ITO strategies to succeed, managers must have a comprehensive understanding of the business they run, as it is important to create conditions that foster inter-firm information sharing. To achieve these conditions, managers should take special care in selecting boundary spanners, who are the pivotal links in competence enhancement. Originality/value While most research focuses on ongoing trust (i.e. trust develops as ITO evolves), this study focuses on initial (i.e. ex ante) trust and analyzes IT vendor proficiency (expert, experienced and reputed) to examine trust as an antecedent of ITO. This study also draws on previous conceptualizations of vendor integration to develop and analyze a two-step integration model to explain how IT vendor integration (i.e. process integration and information sharing) catalyzes enhancement of the buyer’s non-IT competences. This study focuses on SMEs, which are often neglected in ITO studies.