The association between the composition of movement behaviours and mortality risk, acknowledging the composition nature of daily time data, is limited explored. The aim was to investigate how the composition of time spent in sedentary behaviours (SB), light intensity physical activity (LIPA) and moderate-to-vigorous physical activity (MVPA) is associated with all-cause mortality, in a cohort with 15 years follow-up time, using compositional data analysis. Eight hundred fifty-one participants (56% women, mean age 53 years) provided objectively assessed physical activity data using an Actigraph accelerometer and were followed for 15 years. Association of daily time composition of movement behaviours with risk of mortality were explored using compositional data analysis and hazard ratios (HR) of mortality were estimated based on a cox regression model. A significant (p<0.001) positive association between time spent in SB relative to time in other behaviours, and a significant (p=0.018) negative association between time spent in LIPA relative to time in other behaviours, with all-cause mortality, was found. Substituting time spent in LIPA or MVPA with time in SB increased the hazard for all-cause mortality, with greater effect found for MVPA (20 min replacement; HR 1.26, 95% CI 1.04-1.52) than for LIPA (20 min replacement; HR 1.06, 95% CI 0.65-1.73). In a public health perspective, it is recommended to substitute SB with either LIPA or MVPA, but for individuals with little time spent in MVPA, the most important message may be to try to maintain that behaviour.