Ehrlichia canis is a tick-borne rickettsia. It can cause canine monocytic ehrlichiosis (CME). Infected dogs are often reported to have changes in their blood values, such as anemia, thrombocytopenia, increased liver enzymes, and increased kidney function values. This study aimed to collect data that may be related to infected dogs, including age, gender, breed, weight, close-open housing system, the use of ectoparasiticides products. The sample comprised 57 infected dogs. Collecting hematology and serum biochemistry changes in comparison with the reference values of dogs detected with Ehrlichia canis from 2017-2019, Thonburi District, Bangkok, Thailand was also carried out. In summary, dogs infected with Ehrlichia canis mostly included mixed-breed dogs aged between 1 and 10 years. There were no differences in body weight or housing systems. Dogs that had never used ectoparasiticide products or used them intermittently were infected more often (by 7.14 times) than protected. Clinical hematology and serum biochemistry found anemia, thrombocytopenia, and increased liver enzymes.