We have reviewed a case of portomesenteric venous thrombosis that occurred shortly after the administration of the second Pfizer/BioNTech coronavirus disease 2019 (COVID-19) vaccine and discussed the literature surrounding the subject. Our report was generated after reviewing the patient's medical records and clinical images with his written informed consent. The literature review was conducted using PubMed and Google Scholar. Portomesenteric venous thrombosis after the Pfizer/BioNTech COVID-19 vaccine has previously been reported, although infrequently. We did not find enough information, given the paucity of the reported data, to assert a causative relationship between the Pfizer/BioNTech COVID-19 vaccine and the occurrence of portomesenteric thrombosis.