For the first time a serious attempt has been made to understand the social background of the Namdhari Sikhs of Punjab; their demographic and occupational changes and beliefs and practices. The study shows that the Namdhari Sikhs primarily came from the agricultural and artisan classes ever since the inception of the Kuka Movement in the late nineteenth century. Since then the people of other occupational castes have also responded to the Namdhari mission. The study has identified eighteen occupational castes of the Namdhari Sikhs. Among these, the Jat and Ramgharia Sikhs are in majority. The study analyses the variations in the proportionate representation of each occupational caste and its status in the administrative hierarchy of this community during a period of 150 years. It also examines the impact of primary variables, like Partition of Punjab (1947), creation of Indo-Pakistan Border, Green Revolution, industrial developments and Terrorist Movement in Punjab, on the processes of migration and resettlement of the Namdhari Sikhs, their caste-wise occupational diversification and class differentiation and rise of new classes. These developments posed serious challenges to the Namdhari leadership. In addition to the above, the study examines the Namdhari concepts of embodied-guru, nam-simran, structure of rituals, dowry-free mass marriages, food taboos and dress code. The study highlights that the religious orientation of the Namdhari Sikhs has strengthened them spiritually and morally to withstand those social evils that affect most Punjabis.The study is based upon a random survey of 1545 Namdhari families of eighteen districts of Punjab, as well as primary and secondary sources.