The number of women not having children in Spain is increasing. Official data reveals that, since the 1990s, the total fertility rate in Spain has been below 1.5 children per woman. More precisely, the number of women who remain childless in Spain rose from 11 per cent for women born in 1945 to 20 per cent for those born in 1965, and it is estimated to reach 25 per cent for women born in 1975. This means that one out of every four women in this latter generation will not become a mother, making it the Spanish generation with the fewest number of children in the last 130 years. Despite the fact that existing research has determined that poor material or family conditions are the main reason for not having children, the number of women who freely choose non-motherhood is increasing. This chapter explores the various reasons why Spanish women choose non-motherhood. To this end, we conducted a series of interviews with a group of women fitting this profile and asked them to explain why they opted to remain childless. Our survey included questions specifically designed to explore and examine the arguments provided by our interviewees, to identify those aspects of their life experiences that led them to reject motherhood, and to understand the lived realities of being a non-mother. The chapter is also careful to contextualize this study within contemporary Spanish culture and society.