Introduction: One of the common problems among older people is falling. Falling inside the houses and streets makes up a large incidence between Iranian elderly, then the effort to identify environmental factors at home and home modification can reduce falls and injury in the elderly. The aim of this study is identifying elderly at risk of fall with using screening tool (HOME FAST) and define reliability of this tool.Material and Methods: As a reliability, through the health housing of the town councils in five geographical regions of Tehran, 60 old person were selected. Participants aged 60 to 65 years and the HOME FAST tool was used in the two stages (inter rater and test-retest).Results: Test-retest reliability in the study showed that agreement between the items is over than 0.8, which shows very good reliability. The results showed that the relative of the each item in the Agreement between the domain is 1 - 0.65, which shows moderate to high reliability. And the results in this study showed that agreement between the items in Inter rater reliability is over than 0.8, which shows the level of reliability is very good. Also it showed that the relative of the each item in the agreement between the domain is 1 - 0.01, which shows poor to high reliability.Conclusion: This study shows that the reliability of the HOME FAST is high. The findings of these comments have been expected that the test objectives were appropriate to prevent falls and the tools showed acceptable reliability, then this test can be used as a tool for to professionals.