The ability of expert practitioners to make sound judgments when faced with non-routine situations calls on a form of tacit knowing that has been loosely branded as ‘intuition’, a ‘sixth sense’, or ‘gut feeling’. The development of tacit knowledge is associated with nonformal learning that occurs in the context of the workplace; however, the elusive nature of this phenomenon has served to hamper research efforts. The focus has therefore shifted away from tacit knowledge toward the more observable concept of ‘judgment’. Paramedics are called to make clinical judgments as part of their everyday practice, often unaware of the basis behind these judgments. This case study examines the source of knowledge drawn on by experienced paramedics when making judgments, especially when faced with situations they have not previously encountered, and proposes how new knowledge and meaning is constructed through such involvements. A better understanding of the relationship between knowing and judgment, and how they are developed, will have future implications for the provision of ongoing education and training programs for paramedics.