Emerging research has suggested that the nature of cognitive deficits in Amnestic-MCI (a-MCI) may extend beyond memory impairments and can include deficits in attention (Gualtieri & Johnson, 2005; 2007). Recent studies have found significant differences between subjects with a-MCI and cognitively healthy individuals on measures of processing speed (Gorus, De Raedt, Lambert, Lemper, & Mets, 2008; Gualtieri & Johnson, 2005; Levinoff, Saumier, & Chertkow, 2005; Silveri et al., 2007). The current study sought to add to the limited research currently available on processing speed in a-MCI by comparing cognitively healthy individuals (M age = 64.57; SD = 6.61) and an age-matched a-MCI group (M age = 64.19; SD = 5.79) on a measure of processing speed, an index of attention. Second, the study evaluated the utility of the “25 Numbers Test” in differentiating individuals with a-MCI from a cognitively healthy group of participants. As expected, the participants with a-MCI performed more poorly (t(72) = -5.96, p < .01) on the 25 Numbers Test and demonstrated greater intra-individual variability in comparison to the cognitively healthy group (t(72) = -3.009, p < .01). The 25 Numbers Test effectively discriminated cognitively healthy individuals from those with a-MCI (AUC = 0.85, p < .01). Results will add to the limited research on processing speed in a-MCI and provide a basis for the importance of evaluating processing speed as part of routine screening for a-MCI.