Age-related decline in memory and other cognitive functions, such as visuospatial functions is widely studied and well documented. In recent years, some studies have also found relationships between memory performance and functional body lateralization, with individuals who are inconsistently lateralized (e.g. have inconsistent handedness) scoring higher on episodic memory tests. The objectives of this study were to investigate relationships and possible differences between episodic and semantic memory performance, and visuospatial functions as a function of functional lateralization consistency in a large population-based study. In total, 1283 adult men and women participants, with age ranging from 25 to 100 years, were tested within the Betula prospective cohort study (Nilsson et al., 1997) where they were included in the fifth wave (T5) of data collection. Participants were divided into groups of consistent or inconsistent functional lateralization regarding respective hand-, foot-, and eyedness. Results revealed weak to moderate relationship between variables of functional laterality and its consistency. While age was significant predictor of memory performance and visuospatial functions, sex and functional laterality consistency variables were insignificant. Results are discussed in relation to previous studies and to hemispheric interaction theory. / Betula prospective cohort study (Nilsson et al., 1997, 2004)