Objective: This study examines the relationship between the Conners' CPT-II (CCPT-II) scores to WMS-IV scores in a clinical adult population to determine the role attention plays in memory tasks. Method: Participants (n = 247) were composed of 58% females, with an average age of 33.54 (SD = 12.72) and average education of 13.84 (SD = 2.10). The data was derived from an on-going de-identified database. Individuals were given the CCPT-II and the WMS-IV. Results: Pearson correlations were conducted between each CCPT-II T-scores and WMS-IV subtest raw scores. Analyses were considered significant at p < .0001. The CCPT-II Hit Reaction Time Standard Error score significantly correlated with the WMS-IV Visual Reproduction II score (r = −.334), and WMS-IV Symbol Span score (r = −.300); the CCPT-II Variability score was significantly correlated with the WMS-IV Visual Reproduction II score (r = −.303), and WMS-IV Symbol Span score (r = −.315). Conclusion: Results revealed several significant inverse relationships between tests of attentional variability and tests of delayed visual memory. The sustained attention measured in the CCPT-II task might influence one's ability to attend to, and in turn, encode visual stimuli to be remembered in the short-term (visual working memory) and later recall in the long-term (delayed recall). This suggests individuals with impaired sustained attentional abilities display decreased performance in delayed visual memory. Interestingly, omissions and commissions did not significantly correlate with any memory subtest scores. Thus, attentional variability appears more heavily implicated in one's visual memory functioning. Further research should more specifically investigate the relationship between primarily auditory tasks of sustained attention and measures of delayed auditory stimuli recall.