The aim of the present study was to evaluate the effects of dietary ricinoleic acid from castor oil on the milk yield, composition, fatty acid profile and haemato-biochemical profile in lactating Kankrej cows. Twenty lactating Kankrej cows were assigned to the following groups: control (CON), basal diet without any additive and treatment (RAS), basal diet with 2 g/animal/day of ricinoleic acid from castor oil. Dietary ricinoleic acid had no (P>0.05) effect on dry matter intake and feed efficiency. Milk yield (milk, 4% fat corrected milk and energy corrected milk) were not affected (P>0.05) by the feeding of ricinoleic acid. The milk composition showed no significant differences between the groups. A significantly (P<0.05) higher percentage of C4:0, C6:0 and C8:0 was found in the milk from the RAS group than the CON group. A lower (P<0.05) milk C16:0 percentage was observed in the RAS group as compared to the CON. The percentages of C18:2 and C18:3 were found to be increased in the RAS group. There was a decrease (P = 0.055) in milk saturated fatty acids but an increase in milk unsaturated fatty acids percentage in the RAS as compared to the CON group. The milk polyunsaturated fatty acids were significantly (P<0.05) increased in the RAS group. There was no difference (P>0.05) in haemato-biochemical profile between the CON and RAS groups. It was concluded that supplementation of 2 g/animal/day ricinoleic acid from castor oil had no effect on milk yield, milk composition and haemato-biochemical profile. However, it increased the milk fat percentages of unsaturated fatty acids and polyunsaturated fatty acids, and decreased milk saturated fatty acids, without any adverse effect on the health status of the cows.