Breast cancer is a major health burden among women that instils feeling of dread and fear in them. When a woman suffers from this dreadful sickness she will definitely have her physiological and psychological status disturbed due to the worry of loss of her breast, chemotherapy, radiation therapy or any other cumbersome treatment and its complications. It is the time when a nurse can assess her disturbed psychophysiological wellbeing. For this she needs some tool. So the objective of the present study was to develop the Psychophysiological Well-being Assessment Tool (PWAT) based on Roy’s Adaptation Model and to check its validity and reliability.