This research explores the possibility that venture related obsession is experienced by entrepreneurs and, together with passion, contributes productively to desirable entrepreneurial outcomes. Drawing on the literature on obsession (Rachman & Hodgson 1980; DSM-IV 2000; Salkovskis 1985; Davis 2009) and intrusive thoughts (Kavanagh 2005; Fritzler et al. 2008), and the entrepreneurship literature on passion and affect in entrepreneurship (Cardon et al. 2009; Vallerand et al 2003; Baron 2008, Baron et al. 2010), it was theorized that the presence of obsession may contribute to the entrepreneur’s sustained entrepreneurial action (SEA) through the stimulation of passion for their venture. It was further suggested that sustained entrepreneurial action was a necessary precursor to entrepreneurial success. Thus, obsession and passion worked productively together to contribute to entrepreneurial success (ES).