The purpose of this paper is to assess the role of limited tractorization in agricultural development on the basis of data collected through a field survey in the district of Shahabad, Bihar, India which was conducted during 1973-74 1 . It is believed that in a less developed economy where labour is abundant and capital is scarce mechanization (specifically tractorization) in farming would be contrary to the principle of factor proportion and as such would be wasteful. Even if tractorization proves more profitable than animal-operated farming it may be socially undesirable in so far as it leads to displacement and consequent underutilization of human labour. The study attempts to examine how far this actually happens and also the possibility of counter-acting the displacement of human labour by an appropriate combination of tractor operations with manual operations on the basis of custom-arrangement.