Creatine supplementation has shown promise for increasing muscle strength, endurance and tasks of functionality in the aging population. However, the optimal dosage of creatine needed to maximize these potential benefits is unknown. The purpose of this study was to compare the effects of different dosages of creatine supplementation on aging muscle performance and functionality. Using a double-blind, repeated measures design, participants were randomized to one of three groups: Creatine-High (CR-H; n = 11; 59.3 ± 3.2 yrs, wt = 82.6 ± 16.8 kg, BMI = 28.3; 0.3 g/kg/day of creatine + 0.1 g/kg/day of maltodextrin), Creatine-Low (CR-L: n = 9; 58.8 ± 5.9 yrs, wt = 82.3 ± 16.1 kg, BMI = 28.2; 0.1 g/kg/day of creatine + 0.3 g/kg/day of maltodextrin) or Placebo (PLA; n = 11; 57.3 ± 4.6 yrs, wt = 84.1 ± 11.4 kg, BMI = 28.8; 0.4 g/kg/day of maltodextrin) for 10 consecutive days. The dependent variables measured at baseline and after supplementation were muscle strength (1-repetition maximum leg press, chest press, hand grip), muscle endurance (leg press and chest press; maximal number of repetitions performed at 80% and 70% baseline 1- repetition maximum respectively), and tasks of functionality (walking speed, balance). There was a significant increase over time for leg press strength (p = 0.000), chest press strength (p = 0.001), leg press endurance (p = 0.001) and chest press endurance (p = 0.001), with no differences between groups. There were no changes over time between groups for right-hand grip strength (p = 0.571), left-hand grip strength (p = 0.386), walking speed (p = 0.226) or falls (p = 0.414). In conclusion, short-term creatine supplementation, independent of dosage, has no effect on aging muscle performance. Creatine supplementation may have to be combined with resistance training to produce significant muscle health benefits in aging adults.