摘要：objectives The aim of this study was to analyze the psychometric properties(reliability and validity)of the Social Isolation Scale(SIS)in a sample of Portuguese community-dwelling older *** A transversal descriptive study was carried out with a convenience sample of 250 community-dwelling older adults(≥65 years).The survey comprised a sociodemographic questionnaire,SIS,Geriatric Depression Scale-4(GDS-4),6-item Lubben Social Network Scale(LSNS-6),a loneliness self-assessment question,and Satisfaction with Life Scale(SWLS).Construct validity(confirmatory factor analysis)and convergent validity were analyzed,and ISI internal reliability(composite reliability),external reliability(test-retest,intraclass correlation coefficient)and inter-rater reliability(Cohen’s kappa coefficient)were *** Confirmatory factor analysis showed a two-factor model with an excellent index of *** SIS showed significant correlations with LSNS-6(rs=0.47),SWLS(rs=0.26),the loneliness self-assessment question(rs=0.35),and GDS-4(rs=−0.16).SIS composite reliability was good(0.708).The inter-class correlation coefficient varied from 0.84 to *** Cohen’s kappa coefficient ranged from 0.936 to *** SIS has been shown to be a valid and reliable instrument for assessing social isolation among Portuguese community-dwelling older *** professionals,particularly nurses working in community settings,can use SIS to assess social isolation in older adults to design,implement,and evaluate interventions.