Abstract: Nowadays, there is a great interest towards Spirulina-a bluegreen microalga because of its beneficial compounds. The purpose of the present study was to evaluate the effect of dietary Spirulina platensis on milk fatty acid profile of dairy cows. Twenty healthy Holstein crossbreed, average age 4.3 years, in the second month of lactation were allocated in 2 groups. Ten cows in group A served as controls and were fed individually a basal diet, while the other 10 cows in group B consumed the same diet with the daily addition of 40 g Spirulina per cow. The experiment lasted 7 weeks and every 15 days the milk fatty acid profile was evaluated. The results showed that dietary Spirulina decreased saturated fatty acids, whereas it increased monounsaturated and polyunsaturated fatty acids. In conclusion, Spirulina is a promising dietary supplement for the enhancement of cow milk with health-associated unsaturated fatty acids.