Perianal dermatitis is a common problem occurring among infants and children. Streptococci, particularly beta-hemolytic group A organisms, play a major role in its causation. An epidemiologic association between perianal dermatitis caused by group A beta-hemolytic streptococci in some patients and pharyngeal colonization with the same organisms seems to exist. A similar relation is also true for other organisms, including non-group A beta-hemolytic streptococci and Staphylococcus aureus. This was the main conclusion of a hospital-based study performed on 150 children with perianal dermatitis. All patients were subjected to a questionnaire, clinical examination, two perianal swabs, and two throat swabs. The bacteriologic examination of the perianal swabs revealed the presence of beta-hemolytic streptococci in 35.3% of the cases, half of which were of the group A beta-hemolytic strain (17.3%) and half of which were non-group A (18%). Throat swabs revealed the presence of beta-hemolytic streptococci in 44% of cases, half of which were found to belong to group A (21.3%) and half to non-group A (22.7%). Among patients with perianal dermatitis caused by group A beta-hemolytic streptococci, 53.8% had associated pharyngeal colonization by the same organism. S. aureus was isolated from the perianal skin in five patients (3.4%); in four of whom the same organism also grew in cultures from throat swabs. A relatively good association between pharyngeal colonization by beta-hemolytic streptococci and Staphylococci and the presence of perianal dermatitis caused by the same organisms was demonstrated using the Kappa test of agreement (K = 0.4).