The prevalence of nasopharyngeal Streptococcus pyogenes in children attending day care centers in North Jordan was studied. Nasal and throat swabs, cultured for Streptococcus pyogenes were collected from 100 children enrolled in four day care centers serving middle to high socioeconomic status portions of the population in March 1989. The identity of the streptococcal isolates was confirmed by biochemical and serological methods. Throat infection manifestations of the past 3 days, as reported and observed by the care givers, were related to culture results. The study findings showed that the prevalence of nasopharyngeal Streptococcus pyogenes was high and ranged between 10 to 23.3%. It was also noted that the care givers were able to correctly identify children with suspected throat infection, in 11 to 25% of the children who grew Streptococcus pyogenes on cultures, by mere observation of the symptoms. Due to the high prevalence of nasopharyngeal Streptococcus pyogenes in these settings, measures to control and prevent the spread of Streptococcus pyogenes must be employed. This study suggests that care givers may play an important role in achieving such a goal if they are offered proper health education programs and instructions on child hygiene.