A study to assess the viability of commercial dairy farming was conducted in Haryana state during the year 2009-2010. The sample dairy farms were categorized on the basis of milch herds. Proportion of investment on milch animals was found highest in large commercial dairy farms whereas proportion of investment on sheds and machinery was maximum in small commercial dairy farms. The net cost of milk production per litre for milking crossbred cattle on small, medium and large farms was estimated to be R10.68, R10.21 and R9.49 whereas for milch cow R10.89, R10.62 and R9.99 respectively. The net cost of milk production per litre for milking buffalo on small, medium and large farms was estimated to be R15.50, R15.01 and R14.96 whereas for milch buffalo R16.19, R15.62 and R15.73 respectively. About 25.00% of total large farms fell in high technical feasibility category while minimum i.e. 7.14% of total medium farms were found under low technical feasibility. The large dairy farms were economically sound based on the investment pattern, estimates of cost and returns of milk production, overall farm income and technical feasibility in comparison to medium and small commercial dairy farms.