We examine how family context affects one’s desirability to potential marriage partners among the customers of a large Japanese marriage agency. The agency data provide us a unique opportunity to isolate the impact of family characteristics as well as socio-economic control variables on the “demand side” of marriage market interactions. Japan is an important test case of theories about marriage formation in societies where family and kinship are important institutions – theories that so far have mostly been tested on Western data. We show that traits associated with resource commitments, such as living with or having to support family members or being an only child, reduce attractiveness. Natal family characteristics that can be read as proxy of a lower social background, namely having three or more siblings, also reduce one’s desirability, as does a history of divorce. We also find support for the culturally specific argument that expectations of care associated with being the oldest son reduce attractiveness.