The incidence of shigellae was measured in 445 children with diarrhoea in Sanandaj, Kordestan, and 715 in Tehran during a 1-year study. 18 (4%) patients in Sanandaj and 41 (5.7%) patients in Tehran were positive for various shigella species. Sh. boydii (7 strains) and Sh. sonnei (25 strains) were the commonest species in Sanandaj and Tehran respectively. Among the isolates from Sanandaj the highest resistance was to tetracycline (55.5%), whereas in Tehran it was to sulfamethoxazole/trimethoprim (68.3%).