A bacteriological study was conducted on the isolation of Staphylococcus aureus from ruminant milk (Buffaloes, Cow, Sheep, Goat). Four hundred milk samples were collected from these animals (100 samples from each) from different locations in the Ninevah governorate during the period from October 2008 till May 2009. The results showed that the percentage of Staphylococcus aureus isolation from the above mentioned animals was as follows: Buffalos (78%), Cow (55%), Sheep (65%), Goat (49%). Sensitivity test applied on the isolated organisms showed different result between milk samples of different animals and within the same species. It is interesting to note that some of our S.aureus isolates were resistant to methicillin, and thesis resistance was 50% in buffaloes; 20% in cow and sheep and 20% in goat.