One goal of genetic counseling is to facilitate client adaptation to a genetic condition or risk. Adaptation refers to both the process of coming to terms with the implications of the condition or risk and the observable outcomes of that process. This review summarizes existing studies on how well clients adapt to living with a common chronic disease, and more specifically, a genetic condition. Overall, it appears that about one-third of clients do not adjust well to the stress of living with a genetic condition or at risk. However, the data are limited by inconsistencies in the conceptualization of adaptation, a paucity of theoretical models, poor study design and inadequate outcome measures. Well-designed studies based upon multidimensional models are needed that focus on familial as well as individual adaptation. We conclude with a summary of studies that have explored the use of interventions to enhance adaptation and suggest improved client outcomes. Further research should result in evidence-based interventions to facilitate client adaptation that can be used effectively by genetic providers within the confines of their clinical work.