<b><i>Aims:</i></b> We investigated the associations of prospective memory (PM) with memory, attentional control, and conscientiousness and whether they differed between young-old (YO) and old-old adults (OO). <b><i>Methods:</i></b> We analyzed data from 562 older adults (mean = 80.04 years) who were tested on four PM tasks, memory (immediate and delayed cued recall), attentional control (letter and category fluency), and reported conscientiousness. <b><i>Results:</i></b> Latent variable analyses showed that in both YO and OO PM was associated with memory and attentional control (but not conscientiousness). Notably, testing for moderation effects revealed that the relation between PM and attentional control was significantly stronger in YO than in OO. <b><i>Conclusion:</i></b> YO may be able to better (than OO) achieve a good PM performance with good attentional control.