An economic study of adoption of farm mechanization in rice cultivation - a case study in Khammam district of Telangana state, study examined the extent of adoption of farm mechanization and cost of cultivation in Khammam district of Telangana. In total district 120 farmers are selected as sample size. Two mandals, Kalluru mandal and Nelakondapally mandal has been selected. In low adoption category the average total cost of cultivation was high i.e., Rs. 61905.62 per ha. At low adoption category, total variable cost per hectare was Rs. 50704.49 and total fixed cost per hectare Rs. 11201.13 per ha. The cost of cultivation was calculated according to cost concepts also. The cost of cultivation according to cost concepts cost C3 was high for the low mechanized farmers i. e., Rs. 61905.62 per ha. Returns were high for the highly mechanized farmers than low and medium mechanized farmers.