The purpose of this study was to determine the effect of 12 wk of stairclimbing with and without an external load on aerobic capacity and quadriceps strength of sedentary (initial VO2max 25.3 ± 0.73 ml-kg−1.min−1) (mean ± SEM) middle aged females (50–65 yr). Three groups, LOAD (stairclimbing with external load, N = 8), STAIR (no load, N = 9), and CONTROL (N = 7) were tested. By week 4, subjects warmed up 5 min on a cycle ergometer followed by 35 min on the stairclimber at 80–85% maximum heart rate (MHR) 4 d.wk−1. In week 6, the LOAD group carried an external load of 4% of body weight increasing to 8% for weeks 7–12. STAIR and LOAD group significantly increased (P < 0.01) VO2max by 11.1% and 9.6%, respectively. Isokinetic strength tests showed increased (P < 0.05) peak torque and total work for STAIR and LOAD at 120 and 180°.s−1. For total work, a significant increase (P < 0.05) of 10.5% was observed at 60°.s−1 for the LOAD group. The results indicate stairclimbing is an appropriate exercise for middle-aged females improving both aerobic capacity and strength following 12 wk of training.