Objective:To determine the presence of Trypanosoma eransi(T.evansi) and the effect of trypanosomosis on hemato-biochemical profile of dromedary camels in Semnan,Iran,which has not been reported yet.Methods:To perform this project,blood samples were collected by venipuncture into plain and EDTA-K2-containing vacutainer tubes from 21 dromedary camels(12 males and 9 females) aged3—18 years,from 4 different regions of Semnan.Results:Microscopic examination of stained thin blood smears revealed the presence of T.evansi in one of the samples.However,it should be noted that this sample showed a very high parasitemia(more than 5 trypomastigote were visible per microscopic field with MGG,1000×.This heavy parasitemia was associated with an 18-year-old female camel that showed symptoms of corneal opacity,intense emaciation and pale mucous membranes.Comparison of hematological and serum biochemical profiles between the camel infected by T.eransi and uninfected camels indicated anemia,leukocytosis,hyperproteinemia.hypoalbuminemia,hyperglobulinemia,reduction A/G ratio,increased a,,p and globulins and decreased of a,globulins and increased the concentration of gumma-glutamyl transferase enzyme.Conclusions:Results of the present study revealed that trypanosomosis was present in dromedary camels of Semnan,Iran(infection rate is 4.76%) and hemato-biochemical parameters were markedly affected by camel trypanosomosis. Objective: To determine the presence of Trypanosoma eransi (T. evansi) and the effect of trypanosomosis on hemato-biochemical profile of dromedary camels in Semnan, Iran, which has not been reported yet. Methods: To perform this project, blood samples were collected by venipuncture into plain and EDTA-K2-containing vacutainer tubes from 21 dromedary camels (12 males and 9 females) aged 3-18 years, from 4 different regions of Semnan. Results: Microscopic examination of stained thin blood smears revealed the presence of T. evansi in one of the samples. Host, it should be noted that this sample showed a very high parasitemia (more than 5 trypomastigote were visible per microscopic field with MGG, 1000 ×. This heavy parasitemia was associated with an 18-year-old female camel that showed symptoms of corneal opacity, intense emaciation and pale mucous membranes. Comparison of hematological and serum biochemical profiles between the camel infected by T.eransi and uninfected camels indicated anemia, leukocytos is, hyperproteinemia. hypoalbuminemia, hyperglobulinemia, reduction A / G ratio, increased a ,, p and globulins and decreased of a, globulins and increased the concentration of gumma-glutamyl transferase enzyme. Conlusions: Results of the present study study that trypanosomosis was present in dromedary camels of Semnan, Iran (infection rate is 4.76%) and hemato-biochemical parameters were markedly affected by camel trypanosomosis.