Examination of joint kinematics is a useful tool to describe necessary postural adjustments needed while walking sloped surfaces of differing inclination. Further, older adults may use different postural adaptations for sloped walking than their younger counterparts. Before investigating age-related adaptation differences, reliability of kinematic measures has been obtained for both age groups. Healthy, older (n=17, 65+ years) and younger (n=18, range 18-25 years) adults performed four self-selected paced trials under three conditions: walking on level, 10° incline, and 10° decline. Three dimensional ankle, knee, and hip joint (flexion/extension) angles during two phases of gait, ground contact and ground off, were determined using an electromagnetic tracking device (Motion Monitor, IST, Inc, Chicago, IL). Separate ICC(2,1) analyses were conducted for each joint at ground contact and ground off, as well as for each age group. Reliability levels were similar for the two groups as well as the two phases of gait, although ground contact was generally more reliable than ground off. Incline measures were reliable with ICC values ranging from .46 to .96 (with 11 of the 12 ICC's being .68 or above). Decline condition ICC's ranged from .65 to .97. Measurements for the level condition were least stable for the knee and hip at ground off for both age groups and the hip at ground contact for the older adults only (ICC's ranged from .18 to .57). The other seven reliability values for the level condition ranged from .66 to .98. Overall, use of an electromagnetic tracking system to measure lower extremity joint kinematics should be considered reliable for within day measures of gait during the three sloped conditions utilized in the current investigation. This within day reliability may help to provide a comprehensive understanding of potential adaptation patterns of an elderly population when compared to healthy, younger persons. Further, understanding these gait adaptations could provide insight into the causes of falls in the elderly.