Fr. prof. Władysław Piwowarski is known in Poland and abroad primarily as a sociologist of religion. His sociological works are an important component (one would like to say – classic) of the Polish sociology of religion, they have determined and still determine its development. Most of them closed a certain stage in the development of the sociology of religion in Poland and opened a new one. Today it would be difficult to imagine a thorough study of religiosity without taking into account the sociological achievements of Fr. prof. Piwowarski. In this study, we will only focus on selected aspects of his concept of the sociology of religion (sociology of religion as a sociological subdiscipline), religiosity as a subject of sociological research, methodological problems of the sociology of religion). We ignore his scientific achievements in the fields of sociology of morality, social philosophy, Catholic social science and pastoral theology.