Abstract Several studies have established the sortilin-related receptor gene (SORL1) as a susceptibility locus for Alzheimer's disease (AD). Single nucleotide polymorphisms of SORL1 reported in literature as being associated with AD were investigated in an Italian case-control data set, and their role as a risk factor of conversion to AD was studied in an independent sample of subjects diagnosed with mild cognitive impairment (MCI) at baseline. rs641120, rs2070045, and rs1010159 were genotyped in 734 subjects diagnosed with AD (n = 338) and MCI (n = 181) and in healthy controls (n = 215). Our results confirmed the association between rs641120 and AD (p = 0.01). In the MCI cohort, rs1010159 was associated with conversion to AD (HR = 1.56, p = 0.002). Taken together, these findings confirm that SORL1 is associated with AD and might be a potential tool for identifying MCI subjects at high risk of conversion to AD.