The angiotensin-converting enzyme (ACE) and the alpha-actinin-3 (ACTN3) genes have been associated with power phenotypes and both have been suggested to influence skeletal muscle function in response to strength training (Lima et al. 2010). However, conclusions have been inconsistent across investigations. There is a paucity of research data concerning exercise training-induced adaptations in older population (Adams et al. 2000). The purpose of this study was to investigate the possible associations between ACE I/D and ACTN3 (R/X) polymorphisms and maximum strength, power and muscle function in older Caucasian women (n=139; age= 62.5+/-8.1; ID:n=52; DD:n=52; II:n=35 and RX:n=54; RR:n=52; XX:n=33) and their adaptation during 12-weeks of high speed power training. Period of intervention consisted of 40% of one repetition maximum (1RM) to 75% and 3 sets 4-12 reps in countermovement jump (CMJ) (Pereira et al., 2012). Strength was measured dynamically in leg extension exercise (1RMLE), power was evaluated by CMJ and functional capacity was recorded by sit to stand test (STS). ACE I/D and ACTN3 R/X polymorphisms were determined by polymerase chain reaction. Significant differences were performed by ANOVA (means±SD). The trainingxgenotype effects were analyzed by repeated-measures ANOVA. Whole body was independent of ACE and ACTN3 genotypes. At baseline no significant effects of both ACE and ACTN-3 genotype were found for all considered strength parameters. Over the 12-weeks training period, the subjects significantly increased maximum strength (62.9% in 1RMLE), lower limbs muscle power (30% in CMJ) and functional capacity (22.5% in STS test). Genotype effect for ACE showed no statistically difference only in 1RMLE (P=0.187). But subjects with genotype DD had higher maximal strength than others after the high-speed power training. Although, genotype effect for ACTN3 showed significant effects for all measures: 1RMLE (p=0.011), CMJ (p=0.050) and STS (p=0.033). RR genotype exhibited a positive and a prevalence of strength (1RMLE: 33.1±6.4), power (CMJ: 0.164±0.02) and functional capacity (31.3±4.7) comparing to RX and XX genotypes. The combined influence of ACE DD+ACTN3 RR vs. ACE II+ACTN3 XX polymorphisms was also studied. In response to high-speed power training, the results showed that the D-allele carriers and R-allele combination seems to induce significant increases but only for 1RMLE. These data suggest that ACE genotype is not associated with muscle strength adaptation to high-speed power training. On the other hand, strength training response seems to be significantly affected by the presence of the ACTN-3 RR genotype alone or in combination with the ACE DD genotype in older Caucasian women’s. The results provide a novel insight that these genetic variations may interact to determine muscle performance in older women.