Background: Schizophrenia negatively affects both patients and their families. What are the effects of this incurable, potentially hereditary disease on daily life? Related research shows that schizophrenics tend to experience 'uncertainty' in daily life. Discussions on 'uncertainty' experienced in daily life in the context of concerns regarding hereditary illness remain scarce in Taiwan. Purpose: This research was designed to gather important data on schizophrenic patients and their family members related to their uncertainties about disease heredity. Methods: Participants were recruited from the psychiatric unit and outpatient services department at two hospitals in Hsinchu County. Research subjects included a total of six schizophrenics and six family members. Results: The three topics deduced from data analysis included: 1. marriage / family difficulties rooted in feelings of suffering and torture related to the psychosis and uncertainties regarding disease heredity; 2. evolution from doubt to trust as patients gradual accept choices and make decisions related to disease heredity; and 3. dealing with disease heredity again after having made a successful transition (i.e. persistence to maintain family ties). Conclusions / Implications for practice: Both patients and family members experienced worry and fear due to uncertainty about the hereditary condition of the disease. Some experienced emotional responses such as anxiety and helplessness. Research results are expected to help nursing personnel understand the multiple effects and impacts of uncertainty toward illness heredity experienced by the patients and their families in order to provide better consultation and medical care quality under differing circumstances depending on the individual characteristics of patients and their families.