Abstract Objective: The objective of the study was to carry out the factorial validation of the questionnaire for the evaluation of informal social support (ASI) for the elderly. Method: It is a descriptive, observational, quantitative type research. It was executed between August and December of 2016 in the municipality of Natal, Rio Grande do Norte and other locations in Brazil. In Inclusion criteria, were have age 60 or older and cognitive ability preserved. We performed Exploratory Factor Analysis (AFE). As criterion of exclusion of the items was adopted a reference value greater than or equal to 0.35 of factorial load and greater or equal to 0.5 of commonality per item. To determine the amount of retained factors, the criteria of own values>1, minimum cumulative explained variance of 60% and parallel Horn analysis were observed. Results: A sample of 259 elderly people from the five regions of Brazil was obtained. After AFE, 4 items were excluded due to the poverty of their factorial loads, remaining 20 items in 4 retained factors. Conclusion: The instrument has good psychometric properties, such as acceptable factor loads and excellent commonalities.