Background Cryptosporidium is an intracellular protozoan that causes gastrointestinal symptoms in humans and animals. In immunocompromised patients and children under 5 years of age, the infection is severe and can be life-threatening due to severe diarrhea. Case presentation We report a case of urticaria associated with Cryptosporidium in a 17-month-old female Iranian child. The patient had severe diarrhea, weight loss and urticaria. Since the child's father worked in livestock farming, the hypothesis of parasite transmission from cows or calves to the house and the child was proposed. Several Cryptosporidium oocysts were detected in the modified acid-fast staining of the child's stool sample. The patient was successfully treated with nitazoxanide (100 mg twice daily) and became negative for parasites three days after treatment and one week after discharge from the hospital. Her stool pattern normalized in 1 week and she has had no recurrence after 6 months of follow up. Conclusion A number of parasites are associated with urticaria, but to our knowledge, there is no information on Cryptosporidium-induced urticaria. Therefore, our result may be evidence for the role of this parasite in the development of urticaria.