Training approaches in the arena of infant mental health are evolving, demand for training experiences is growing, and recognition of challenges to building the infant-family workforce is improving understanding of training needs. The diversity in the prospective workforce creates challenges for training programs, for example, how to clearly define appropriate training objectives, how to define relevant knowledge base and skills, how to structure training approaches for such a heterogeneous population as the infant-family workforce, and how to provide training experiences that facilitate ongoing professional development for individual practitioners. Workforce diversity is not the only or even the most important challenge however. Work with infants, toddlers, and their families is made up of a great variety of problematic situations, each unique to a baby and its family, each requiring naming and framing. Thus, the complexity of training in infant mental health can be construed as the twin challenges of acquiring needed knowledge bases and also gaining the skills of naming and framing, or of problem setting, which are necessary for effective and reflective practice. The challenges for educators in infant mental health are not only to transmit appropriate knowledge bases in the training process but also to prepare the trainee to work within an ongoing relationship with each family. These training issues will be addressed through an attempt to characterize the work of infant mental health using Schön's framework of reflective practice to further develop the tasks of problem setting in the indeterminate swampy zone of infant mental health practice.