Nowadays, it has been proven that infection with some pathogens, such as certain viruses, bacteria, and parasites, is one of the most important and preventable causes of cancer worldwide. Human toxocariasis is a helminthic zoonosis infection caused by the larvae of the ascarid worms of Toxocara spp. The present study aims to evaluate the seroprevalence anti-T. canis antibodies among cancer patients from Isfahan province, Central, Iran. A total of 97 patients including 16 prostate, 48 gastrointestinal tracks (GIT), and 33 breast cancer patients referred to the Seyedo-Shohada hospital in Isfahan city, central Iran and 30 healthy volunteers as control group were screened for IgG anti-T. canis antibody by enzyme linked immunosorbent assay (ELISA). Structured questionnaires were used to obtain information on risk factors for T. canis infection. Totally, 3 (2.4%) samples from both groups were found seropositive for anti-T. canis antibodies. None of the 16 prostate cancer patients were positive for anti-Toxocara antibody; whereas 4.2% (2/48) and 3.1% (1/33) of GIT and breast cancer patients were found positive for anti-T. canis antibodies, respectively. There was no significant difference in T. canis IgG positivity between the cancer patients and control group (p= 0.2). The results showed contact with dog was not associated with the seropositivity of T. canis. According to the obtained results, there was no evidence of association between T. canis infection and cancer risk. However, further studies should explore T. canis-related effects on cancer risk in larger sample size.