Unwanted birth is a complex phenomenon to understand which need special attention. The specific objectives of the present study are summarized as to examine the consistency of reporting last birth as an “unwanted” by using the concept of ideal number of children. Second to examine the possible reasons of unwanted pregnancy and also find out the determinants of inconsistent response and the last objective is to examine the associated factors of unwanted births by using matching case-control design. Finding of this study revealed that unwanted childbearing obtained from direct method is likely to be underestimating than actual level. Analysis based on among family planning method users show that, 40 percent ever married women had discontinued using contraceptive because they become pregnant while using. One of the finding of this study is that twenty seven percent responses were inconsistent. Finding of Case-control study shows that region, religion, sex of last child, ever used contraceptive, sex composition of living children, experience of child loss and birth interval were emerged as the most important determinants of unwanted birth.