This research aims to determine the attitudes of Millennials towards marriage and parenthood as well as differences in the attitudes towards marriage and parenthood with regard to gender, age, level of education, place of residence, religiosity and tradition. The aim of this research is to see the attitudes of the generation of Millennials about marriage, parenthood and cohabitation. Thus, this paper seeks to find out how strongly a generation of Millennials approves or disapproves cohabitation, the decision that a person never wants to become a parent and the decision that a person has a child with the person with whom he or she lives in cohabitation. Furthermore, it is sought to find out what age Millennials consider ideal for marriage, for fulfilling a parental role as well as the ideal age for starting life in cohabitation. The research was conducted by the method of analysis of secondary data sources on a sample of 469 respondents aged 18 to 38 years from Croatia. Data were taken from the European Social Survey which was conducted in 2018/2019.