Interest in the sociology of human fertility has increased in recent years as it is one of the important factors in the accelerating growth of population. In fact the ever increasing population has compelled social scientists and demographers to undertake in depth studies to understand dynamics of population problem. Their concern has been to understand diverse dimensions of the problem of human fertility and its dynamics. The present study is an endeavour in this field in northern India. The main objective of the study is to examine the present levels of fertility among different socioeconomic and religious groups and to examine some of the sociological correlates of fertility behaviour among the rural communities of Punjab and Haryana which are undergoing rapid economic transformation. The uniqueness of the study lies in highlighting the hitherto neglected area of intra-village and inter-village variations and providing explanations for these variations in observed differentials in fertility behaviour. A significant finding of the study is that land-owners have lesser number of births as compared to landless due to the fear of downward mobility and fragmentation of land holdings. Caste status and family structure has been found to be another important factor indicating variations in fertility. Inter-village variations in fertility are quite significant and they seem closely related to the level of socio-economic development of the villages indicating thereby the key role of socio-economic development in the reduction of fertility. The study would prove to be of immense interest to those interested in the dynamics of population in general and to the policy makers in particular.