Background and Objective : The present study analyzed published research regarding illness-related ‘uncertainty’ experienced by patients and their families and clarified and verbalized ‘uncertainty’ content and expression in order to obtain nursing suggestions regarding managing uncertainty as an issue of adaptation. Subjects and Methods : Japana Centra Revuo Medicina was searched for original articles published between January 2001 to July 2011 using the key words "uncertainty" and "nursing". Content analysis was conducted on the 35 articles that had similar research topics and that investigated patients and families as subjects. Results : The following five categories of research content were extracted : uncertainty due to 1) ‘lack of confidence in somesthetic perception’, 2) ‘inability to assess situation because of lack of relevant information’, 3) ‘lack of future prospects’, 4) ‘inability to predict disease state or treatment outcome’, and 5) ‘inability to extract meaning of life from anxieties about imminent death’. The category of ‘uncertainty due to inability to assess situation because lack of relevant information’ had the heaviest weighting. Conclusion : The present findings suggest that provision of relevant information and listening to uncertainties are important issues for enabling patients and families to accept uncertainty and move toward adaptation.