Background: Although most individuals experience successful weight loss following Roux-en-Y gastric bypass (RYGB), weight regain is a concern, the composition of which is not well documented. Our aim was to evaluate changes in body composition and handgrip strength as a measure of functional status in participants from a previous 1-year post-RYGB longitudinal study who had undergone RYGB approximately 9 years prior. Methods: Five women from an original larger cohort were monitored pre-RYGB and 1.5 months, 6 months, 1 year, and 9 years post-RYGB. Body composition was assessed at all time points using dual energy x-ray absorptiometry and multiple dilution. Handgrip strength was measured using a digital isokinetic hand dynamometer (Takei Scientific Instruments, Ltd, Tokyo, Japan). Results: Mean time to final follow-up was 8.7 years. Lean soft tissue (LST) loss over the similar to 9-year period was on average 11.9 +/- 5.6 kg. Compared with 1-year post-RYGB, 9-year LST was 4.4 +/- 3.0 kg lower (P = .03). Fat-free mass decreased over the 9-year period by 12.6 +/- 5.8 kg. Mean fat mass (FM) decreased from 75.4 +/- 22.6 kg pre-RYGB to 35.5 +/- 21.5 kg 1 year post-RYGB but then trended toward an increase of 8.6 +/- 7.0 kg between 1 year and 9 years post-RYGB (P = .053). Loss of LST was correlated with loss of handgrip strength (r = 0.64, P = .0005). Conclusion: The continued loss of lean mass associated with decreased handgrip strength occurring with long-term trend toward FM regain post-RYGB is concerning. The loss of LST and functional strength carries particular implications for the aging bariatric population and should be investigated further.