BACKGROUND: Domestic pigeons (Columba livia domestica AIMS: To investigate cryptosporidiosis in domestic pigeons in Tabriz, Iran, 100 privately owned pigeons presenting weight loss and diarrhea were tested for Cryptosporidium spp. through parasitological, histopathological, and molecular tests. METHODS: Modified Ziehl-Neelsen-stained fecal smears and histological sections of the trachea and small intestine were examined microscopically. Genomic DNA of fecal and tracheal specimens was examined by nested conventional PCR targeting RESULTS: All pigeons were positive at PCR in their feces and trachea. Oocysts similar to the size of Cryptosporidium species were observed in stained fecal smears of 62% of pigeons. At the histopathological examination, Cryptosporidium CONCLUSION: Considering the high frequency of cryptosporidiosis reported here in symptomatic birds and that both identified Cryptosporidium species are zoonotic parasites, findings claim a public health risk assessment of this species of animals.