Background: More sensitive indicators of cognitive decline are needed in Primary Care. Self-report measures offer some potential but, to date, are not yet reliable indicators of objective performance or progression to dementia. Relationships between self-reported and objective performance remains unclear. Recent research suggests that prospective memory (PM) failures might reflect current and future cognitive decline more accurately than retrospective memory (RM) failures, yet PM is rarely assessed in clinical practice. Methods: In order to determine the nature, extent and possible underlying causes of self-reported cognitive difficulties in older Irish adults, Study 1 obtained PRMQ data as well as sociodemographic, mood state and health-related information from 518 community-dwelling adults >50+ years using an anonymous survey. Study 2 obtained PRMQ data and data on objective tests recommended for Primary Care from a separate sample (n = 97) of community dwelling adults without history of dementia. Participants were then classified as high reporters/low reporters of memory difficulty and the effectiveness of objective tests for determining group membership was assessed. Study 3 employed advanced statistical methods in an attempt to identify an improved self-assessment tool (short-form PRMQ) that might prove useful in primary care whilst Study 4 generated normative data specific to older Irish adults (both for the long-form and the proposed short-form PRMQ) and examined the potential utility of the proposed short-form PRMQ for case-ascertainment. Results: Study 1 data revealed that self-reported PM and RM failures are common in the older Irish population and are related, at least to some extent, to sociodemographic, mood state and health-status. Results from analysis of relationships between objective and subjective memory performance (Study 2) revealed complex relationships dependent upon factors such as mood state and multimorbidity. Study 3 resulted in a short-form PRMQ that does not compromise the psychometric properties of the long-form, whilst Study 4 resulted in normative data conversion tables and a proposed algorithm to aid GPs in their decision-making. Conclusions: The relationships between self-reported memory failures and objective memory performance are complex but can be better understood when account is taken of co-morbidities such as mood state, sleep disturbance and multimorbidity. Based on these findings, care should be taken to understand the complexity and clinical relevance of self-reported difficulties in older adults but recognising atypical reports of everyday memory failures in older adults is worthy of greater consideration in primary care practice.