Dispositional optimism and other positive personality traits have been associated with longevity. Using a familial approach, we investigated the relationship between parental longevity and offspring's dispositional optimism among community-dwelling older subjects. Parental age of death was assessed using structured questionnaires in two different population-based samples: the Leiden Longevity Study (n = 1,252, 52.2% female, mean age 66 years, SD = 4) and the Alpha Omega Trial (n = 769, 22.8% female, mean age 69 years, SD = 6). Adult offspring's dispositional optimism was assessed with the Life Orientation Test-Revised (LOT-R). The association between parental age of death and levels of optimism in the offspring was analysed using linear regression analysis within each sample and a meta-analysis for the overall effect. In both samples, the parental mean age of death was positively associated with optimism scores of the offspring. The association remained significant after adjustment for age, gender, living arrangement, body mass index, smoking status, education and self-rated health of the offspring. The pooled B coefficient (increase in LOT-R score per 10-year increase in parental mean age of death) was 0.30 (SE = 0.08, p < 0.001). In conclusion, parental longevity was positively associated with optimism in adult offspring, suggesting a partial linked heritability of longevity and optimism.