Background: Numerous studies have predicted cancer adaptation and study of attachment styles, hardiness, and social support in cancer patients. But research that predicts cancer adaptation in the family environment based on attachment styles, hardiness and social support has been overlooked. Aims: To predict cancer adaptation in the family environment based on attachment styles, hardiness, and social support. Method: The research was descriptive-correlational. The statistical population of the study was all men and women aged 18-68 with cancer referred to the oncology clinic in 2017-2018 in Isfahan. A total of 203 cancer patients who underwent medical treatment and chemotherapy were purposefully selected. The istruments of this research were: Hazen and Shavar Attachment Styles Questionnaires (1987), Hardiness Questionnaire (Barton, Ursano, Wright and Ingramham, 1989), Social Support Questionnaire (Zimet and Dalhem, 1988) and Psychosocial Adaptation Questionnaire with diseases (Derogatis and Derogatis, 1990). Data analysis was performed using Pearson correlation coefficients and hierarchical regression analyzes. Results: Adaptability to cancer in the family environment can be predicted by the variables of hardiness, attachment styles and social support, and hardinees, secure attachment style and social support in adaptation with cancer had a positive and significant correlation (P< 0/05). Conclusions: Hardiness, secure attachment, and social support were important sources of cancer adaptation in the family environment.