Ageing is part of a continuum which is characterized by developmental and emotional changes as well as cognitive losses and gains. There is evidence that the perception of life quality in the elders is influenced by the level of efficiency of cognitive functions and personal beliefs on the senescence (e.g., De Beni, 2009). Indeed, when the early cognitive decline is negatively perceived, the late adults tend to show low self-esteem, social retirement, depression, low general life satisfaction. Overall, in geriatric studies scales designed to detect subjective psychological well-being are usually administrated ignoring the disturbing effect of several factors, such as the socially desirable responding, a construct referring to the attitude to project favorable images of themselves on questionnaires or during social interaction (e.g., Knauper et al., 2004). The present study was aimed to investigate whether social desirability is related to several measures of memory and metacognitive efficiencies. Forty-eight young (i.e., 20–30 years old) and old (i.e., 65–74 years aged) participants recruited in Ogliastra (e.g., an area in Sardinia known for the high prevalence of centenarians) were individually administrated a battery of tests including the Italian version of the Crowne-Marlowe Social Desirability Scale (Saggino and Perfetti, 2003) together with a measure of subjective mnestic efficiency for daily life facts (Questionnaire on Cognitive Failures, De Beni et al., 2008) and a self-report memory beliefs questionnaire (Cornoldi and De Beni, 2003). The results show that the measurement of the perceived mnestic and metacognitive efficiencies are susceptible to socially desirable responding.