fifteen multiparous Friesian cows with live body weight (LBW) of 510-532 kg and 2-4 parities were used at 45 days prepartum and continues until 120 days post-partum and divided into three similar groups (5 in each group) for study the effect of Spirulina additive on their productive and reproductive performance. Group 1 was unsupplemented which was served as control (G1), or supplemented with Spirulina and their media at the levels of 1 ml (low level) or 2 ml (high level) / kg LBW in drinking water for tested treatments G2 and G3, respectively. Spirulina was grown in a modified Zarrouk,s medium for 21 days. Results showed that digestibility of all nutrients and feeding values of G3 were significant higher (P<0.05) than those of either of G1 or G2, and also all values of these items were significant higher than those of G1. Total DMI was insignificant increased with G2 and significant increased with G3 compared with that of G1. Ruminal pH values did not significant affected by treatments, while TVFA's was increased significantly with increasing Spirulina supplement in dietary treatments and NH3-N values had an inverse trend among treatments. Most blood biochemical and haematological parameters were markedly increased with increasing the algae level in drinking water of cows. Live body weight and body condition score decreased gradually until reach 90, 75 and 60 days and increased thereafter for G1, G2 and G3, respectively. Group 3 recorded significantly (P<0.05) the highest daily yield of actual milk and 4%- FCM, colostrum and milk composition, feed and economic efficiencies and the lowest electrical conductivity in milk. Concerning reproductive traits, cows in G3 recorded significantly (P<0.05) the short periods from parturition until the first estrusand insemination, as well as days open, the highest conception rate and the lowest number of service per conception. In conclusion, cows supplemented with Spirulina and their media at the level of 2 ml/kg LBW in drinking water showed the best results concerning productive performance and body condition score as well as post-partum reproductive trait