BACKGROUND AND AIMS: The level of physical functioning (PF) late in life has, in recent years, been shown to be influenced by genetic factors. One of the most extensively studied genetic variants associated with PF and trainability is insertion/deletion (I/D) polymorphism in the gene encoding Angiotensin Converting Enzyme (ACE). However, ACE studies have mainly been conducted among younger persons in excellent physical shape. In this study, we examine whether the level of PF, trainability, or rate-of-change are associated with the ACE genotype among the elderly. METHODS: We used data from 4 randomized training studies of elderly Danes (N = 203). The measures of PF were self-report, maximal oxygen uptake, muscle strength, walking speed, and body composition. RESULTS: Overall, a favorable change in the measures of PF was observed in training groups compared with control groups. However, within groups, neither pre- or post-training/control period levels of PF nor differences in pre- and post-levels were associated with the ACE genotype. CONCLUSIONS: On the basis of our randomized studies, we could not detect any association between the ACE genotype and the level of PF or change, regardless of whether response to physical training or spontaneous changes was studied.