During the past years, the use of tests and test scores as one critical indicator in education has played a significant role in determining Iranian students’ educational future and their pass to higher levels. The Supreme Board of Education verified assessment reform and the tentative administration of formative assessment in some selected primary schools from 1381-82 scholastic year to resolve negative outcomes of traditional testing. The mentioned plan was administrated tentatively during the present year in grades 4 and 5 of some educational districts in Tehran. This research was aimed at investigating principals’, associate principals’, teachers’ and parents’ attitudes towards the proposed plan. The research design was survey method and the data were gathered through questionnaire. The statistical population of students’ parents under study in Tehran was equal to 2116; and the cluster sampling method was used. Based on the geographical position, one district was randomly selected from each Zone and from each school one Grade 4 and one Grade 5 were studied. The sample consisted 10 classes of 300 parents, 5 principals, 5 associate principals and 10 teachers. The findings indicated that: 1) The plan administrators (principals, associate principals and teachers) regarded the plan as relatively successful in the research sample; 2) Principals’, associate principals’, teachers’ and parents’ attitudes were more positive in female-student schools; 3) In the students’ parents’ view, the plan was highly successful; 4) There was a significant relationship between each questionnaire item and variables of zone, school type, gender, age, education and job, when studying parents’ responses.