Although the Myers-Briggs Type Indicator (MBTI) is widely deployed in work organisations, very little is known about how HR practitioners customise it for use, how employees react to being typed, and how (or if) they apply it in their daily work. This article reports the findings of a study that used interviews with HR practitioners and employees to investigate perceptions and uses of the MBTI in an Australian manufacturing site. A variety of interpretations and uses was found, illustrating that the effects of a device like the MBTI cannot simply be read off from the normative claims contained within it. Despite the variety of uses to which the tool was put, employees judged its effects to be moderately beneficial.The Myers-Briggs Type Indicator (MBTI) is one of the most popular psychological instruments in the world. Each year, two to three million people fill in MBTI questionnaires (Gardner and Martinko 1996; Center for Applications of Psychological Type). Many of these do so in work organisations, as part of HR interventions that use the MBTI to enhance self-knowledge, interpersonal understanding and teamwork. Despite its widespread use, however, little is known about how HR practitioners customise and deploy the instrument as part of their professional toolkits, or how employees, once typed, use (or do not use) knowledge of type in their daily work. Although there is a large literature on the MBTI, much of it is prescriptive (for example, Jessup 2002), or focused on the tool's psychometric properties and ability to predict variables such as creativity and career choice (e.g., Wang, Wu and Horng 1999).Literature that is critical of the MBTI is also often directed at its psycho-