Many factors influence the donation rate such as; social factors, religion, familial relations and level of knowledge and attitude. Level of knowledge and attitude toward tissue and organ donation and transplantation plays important role in willingness to donation after death. Increasing the public awareness can reform the incorrect believes and myths to donation and transplantation. This study investigated knowledge and attitude of donor cardholders in relation to organ and tissue donation and transplantation. This case-control study was done in 2006 in Iranian Tissue Bank. 178 donor card holders and the same number of control group completed a questionnaire including 23 questions about different aspects of donation after death and demographic information. Knowledge and attitude toward donation and transplantation in cardholders was significantly higher than control group (P value< 0.05). There was a reverse correlation between the age and positive attitude toward donation and transplantation in cardholders. This investigation suggested that the main reasons for refusal to donate tissue and organ were insufficient knowledge and negative attitude due to misinformation regarding the donation and transplantation. We believe that educating and motivating the public with mass media can increase the rate of consent for tissue and organ donation and transplantation.