Measurements of relaxin and acute-phase proteins have not been validated for use in canine serum as a method of pregnancy diagnosis. This means that handling and anesthesia is still necessary to check the pregnancy status of most non-domestic canines. Therefore, the intention of this study was to determine whether relaxin and/or acute-phase proteins could be detected in the urine and/or feces of the domestic dog in order to evaluate the potential for a noninvasive pregnancy test in canines. Blood, urine and feces were collected from 18 domestic dogs and assayed for the presence of relaxin, fibrinogen, alpha-1 acid glycoprotein, and ceruloplasmin. Urinary relaxin appeared to be significant for detecting pregnancy of 30 Days or more in the domestic dog. Additionally, further research might shed light on the presence of relaxin in the feces and fibrinogen and AGP in the urine of the domestic dog and their significance for pregnancy diagnosis.