In this paper, we consider Cartan null Bertrand curves in Minkowski 3-space. Since the principal normal vector of a null curve is a spacelike vector, the Bertrand mate curve of a null curve can be a timelike curve and a spacelike curve with spacelike principal normal. We give the necessary and sufficient conditions for these cases to be Bertrand curves and we also give the related examples.
Gökçek et al. (Fri,) studied this question.