Modern PM methodologies emerged in the late 1950s and were formalized in 2012 in an International Organization for Standization (ISO) standard: ISO/FDIS 21500:2012, Guidance on Project Management. This ISO standard follows traditional waterfall approach whereby high-level project definition is used to develop a detailed plan guiding the execution of all deliverables. Agile principles (AP) emerged in the late 1950s and were formalized in the 2001 Agile Manifesto (Larman and Basili, 2003). These principles are not reflected in the ISO standard because agile and waterfall approaches were formerly considered as ‘competing bipolar choices’ (Batra et al., 2010, p.380). Recent research contends that both approaches can be valid, dependent on project complexities and risks (Boehm and Turner, 2003), and that a combined (cocktail) approach could prove optimal (Kahkonen, 2004; Batra et al., 2010; Barlow et al., 2010). This paper investigates combining the AP with a waterfall PM model and compares the new ISO standard to the Agile Manifesto and previous literature on hybrid PM models. We present a novel cocktail model that balances the structure of waterfall-based models with the flexibility of AP. This model has the benefit of meeting the financial, legal and procurement standards of large companies through its use of the ISO standard elements, while introducing the agility required to adapt to changing priorities and environments.