Four bryozoan species were identified from the Mississippian (Viséan) Mobarak Formation of northern Iran: the cystoporates Fistulipora longituba Yang and Lu, Fistulipora djebaglinica Nikiforova, Fistulipora sp., and the trepostome Hinaclema sakagamii Schastlivtseva. The cystoporates are represented by large massive, mainly multilayered colonies, whereas Hinaclema sakagamii encrusts (often also multilayered) on two colonies of Fistulipora. The identified species show palaeobiogeographical relationships to the Mississippian of China, Kazakhstan, and Uzbekistan.