Background Subjective cognitive decline (SCD) is known as the intermediate stage between normal cognitive aging and mild cognitive impairment (MCI). Although elderly with SCD usually perform close to normal in standardized tests, the detailed function of attention networks in this group has not been studied yet. Aims The purpose of this study was to investigate the performance of attention networks, as a possible indicator of cognitive disorder, in older individuals with subjective memory complaint and MCI. Method The attention network test (ANT) was used to examine and compare the performance of three attention networks of alerting, orientation, and executive control in 17 elderly with SCD, 30 multiple domain amnestic MCI subjects, and 15 healthy controls. Results Although the orienting network had almost the same performance in all groups (p = 0.25), the performance of alerting (p = 0.01) and executive control networks (p = 0.02) were significantly different among the three groups: the SCD group performed poorly in both networks compared with the controls and did not differ significantly from the MCI group (p >= 0.05). However, controlling for general age-related slowing abolished the group difference in executive control index. More importantly, our results showed that alerting network that was affected in SCD group had high sensitivity in differentiating this group from controls (0.94%). Conclusion Our data suggest that despite normal performance in neuropsychological tests, the SCD elderly may face significant degrees of attention processing problems, especially in maintaining alerting to external stimuli which might be helpful in diagnosing individuals at risk and designing proper attention-based interventions.