It’s not easy being lean. And for many companies, getting lean right the first time does not always happen. Lean is a management philosophy focused on identifying and eliminating waste throughout a product’s entire value stream, extending not only within the organization but also along the company’s supply chain network. Lean promises significant benefits in terms of waste reduction, and increased organizational and supply chain communication and integration. Implementing lean, however, and achieving the levels of organizational commitment, employee autonomy, and information transparency needed to ensure its success is a daunting task. This article describes in detail two lean implementation projects within the same company: a global manufacturer of food processing machines and equipment. The first project was a failure, while the second is viewed as a success. Examining these projects in detail, the major criteria and conditions that led to either lean failure or lean success are identified. Based on these conditions, we highlight a number of lessons learned, all of which may help other organizations ensure the success of their own lean implementation and improvement efforts.