In this study, changes in birth weight of kids associated with birth type and sex, and the biological basis of difference in birth weights within litter and inbreeding depression on birth weight were investigated. The records from 1995 up to date of the Turkish Saanen goat herd of Canakkale Onsekiz Mart University were used in the study. Single born kids were more advantageous to twin born kids in terms of birth weight (BW) (P<0.05). With respect to litter weight (LW), male twin kids were found heavier (P<0.05). The difference between birth type and sex groups in terms of birth weight difference within litter (LWD) was not significant (P>0.05). A 10% increase in inbreeding coefficient of kid resulted in a decrease in birth weight by 118 g (P<0.05). A similar increase in inbreeding coefficient of mother reduced kid birth weight by 330 g (P<0.05). Inbreeding of kid was important on LW (P<0.05), however LWD and survivability were not affected by inbreeding depression (P>0.05). BW should be evaluated as a trait of mother in terms of birth type x sex interaction. LW can be ignored as a trait in breeding programs. LWD trait does not have a biological basis. Inbreeding depression in BW reported in this study suggested that inbreeding depression should be taken into account in mating programs. In addition, intensive selection on BW should be carried out.