Rotation Primary education of Iran has experienced dramatically demographic dynamics during the last few decades. The number of pupils has increased drastically and continually until early 1990s, but after that somewhat decreased. Along with, the numbers of staffs, teachers, schools and classrooms have changed as well, and these reflected in demographic indices of primary education. Most of these indices, such as pupil to teacher ratio, pupil density in classroom and school and expenditure per pupil improved in 1970s, but it reversed in 1980s and got away from desired standards. These indices improved again in 1990s. Affective proximate factors to this trend included the trend of population growth of the country and dramatic raise in the enrolment rate. Enrolment rate increment was a powerful factor in urban area till mid 1980s and in rural area till mid 1990s. Today, almost all of children 6-10 year old have enrolled in primary education. The sex ratio in primary education decreased continuously and reached below 105 in last period of study. Infant and child mortality increment, between population factors, was an important element of increase in the number of pupils. Fertility began to decline from mid 1980s and this led to intensive decrease of pupil population in 1990s. External migration had its own influence on the number of pupils since there were enormous Afghan and Iraqi refugees during 1980s. With regards to the internal migration, one of its consequences was the urbanism of pupil population in primary education. Decrease in the number of pupils continued up to the present. However, based on population momentum, it is anticipated that the trend will be reversed in upcoming years. Anyway, today it can be said that the growth rate of pupils is nearly equals to the growth rate of 6-10 year old children and henceforth, enrolment rate has not considerably been affected.