The paper examines intergenerational transmission of 'religious capital' from parents to their offspring, within an economic framework of a production function of 'religiosity' where parental inputs serve as factors of production. The database used for the empirical analysis is based on a unique, rich, large-scale survey (2488 interviews) that has been conducted in 1998 in all 47 Spanish provinces. In addition to information on the religious affiliation of the respondent and his parents It has detailed data on two dimensions of the individual's religiosity: mass attendance (a public religious activity with utilitarian/social motives-has six alternative levels); and prayer (an intimate/private religious activity with pure religious motives-11 levels).It also includes information on the mother's and father's church attendance when the respondent was a child (nine levels) as well as the respondent's mass participation at the age of 12. Socio-economic background data are also available. While most empirical studies are employing one dichotomous variable to measure religiosity (e.g. goes to church-yes/no; practicing Catholic- yes/no), our data base provides much more details on religious activities of respondents and their parents, thus facilitating a more sophisticated analysis with more robust conclusions. The inputs of the parents are proxied by the mother's and father's intensity of church attendance when the respondent was a child. The output (respondent's religiosity) is measured using detailed data on the two aspects of the individual's religiosity: mass attendance and prayer. Socio-economic background variables, that might affect religiosity, are also considered. A theoretical framework is followed by stylized facts on the household composition (in terms of religious affiliation and level of religiosity of the mother and father). Then the effect of the parents' input on respondent's religiosity is examined - first using cross-tabulation and then using regression analysis that facilitates the estimation of the various net effects and their interactions. All in all we find that parental religious inputs significantly affect individuals' religiosity. The route of intergenerational transmission is from both parents to children. However, for women the more pronounced route is the mother, while for men- transmission is flowing mainly through the father. An exception is prayer habits of men that are affected more significantly by the mother's input. We do not find substitution or complimentarity between the impacts of inputs of the mother and the father. This study contributes to our understanding of religious behaviour in Spain and is responding to the growing interest in religiosity in the European Union, as expressed by the outlines of the seventh framework research agenda.