Head louse infestation is common in various parts of the world. Baluchestan area in southeast of Iran is one of the most infected areas. We studied the head louse infestation among the girls in primary schools of Iranshahr, which is the largest city of the province during November 2002 to May 2003. Totally 918 pupils, between 6-14 years old from 12 urban primary schools were randomly selected by multistep method. Inspection was carried out by dividing the scalp to four sections with rat-tail comb in a well lighted area for about 3-5 minutes. Those suspected of having lice were subjected to comb with a fine – toothed comb for about 7 minutes over a white paper of 60 × 75cm size. Children, whose hair had at least one of the developing stages of parasite including only nits located ¼ inch from the scalp, were considered positive. Children’s age and some hair characteristics including wavy, hair etc in addition to hair oil usage and presence of dandruff were shown to be associated with infestation. The prevalence rate was shown to be 27.1%. Our study indicates that older pupils were more infested than the younger ones. Negative association between infestation rate and dandruff was observed, but application of oil and infestation rate indicated positive correlation. According to our research, using hair oil make scale suitable for infestation, but hair cut, as School authorities recommends has no effect.