The study achieved isolating Campylobacter spp from  diarrheic and non-diarrheic  cows  and studying the percentage of diarrhea in 10 areas in Baghdad governorate (AL Shaeluh, Abou Ghurayb , Khadmyia , Sadar city , Suwyria, Mahmudyia, Latifyia , Alridwaniuh, Hur Rajb  and Yousfyia), One thousand fecal  samples were cultured on different selective culture media specific for Campylobacter spp  ,and different biochemical tests  were used (oxidase reaction, Oxoid biochemical identification system campy, Tripple Sugar Iron ( TSI)  , hippurate hydrolysis and the use of Vietik (NH). Eighty isolates of  Campylobacter spp were recorded ( 8% ).Campylobacter spp isolates included C. jejuni 30(3%)  C. coli 30(3%) and C.lari 20(2%). High percentage of diarrhea  was recorded in Hur rajb and Abou Ghurayb 70(82.35%) , 81 (81.81 %) respectively while lower percentage of diarrhea  was in Mahmudyia and Yousfyia in percentage 43(39.09%).50(46.72%), High  percentage of campylobacter  isolates was recorded in AL shaeluh  15 (18.75%)  , while lower percentage of isolates was recorded in Hur rajb and Yousfyia 5(6.25%), 4(5%) respectively .  Age  group one day to one month  gave the highest  isolation rate  50 %(40) while lowest isolation rate in age group(6 months to 1year) 5% ( 4)   under (P ˂0.0001)  level. The highest  isolation rates were  recorded in Summer 2016(19.16%) and Summer 2017 (24.32%) while the lowest isolation rates  was recorded  in Winter (0.8%). Animals infected with C. jejuni and C coli , showed obvious clinical signs including  depression, loss of appetite and inability to feed newborn calves, they suffered from severe diarrhea and dehydration,  and the presence of blood and  thick mucus , high fever were observed in some animals, while  in animals infected with C.lari  the  clinical signs,  were mostly  within normal  limits  .It can be concluded that two species of campylobacter( C.coli and.C. Lari) isolated from diarriheic cows,are  new species added to the two species of campylobacter (C. fetus and C.Jejuni) previously isolated from cows in Iraq and increasing the total campylobacter species confirmed in Iraq to four spp.