To evaluate the effects of prehabilitation (enhancing physical capacity before total hip or knee joint arthroplasty) on pain and physical function of adults with severe hip and knee osteoarthritis (OA). Consecutive patients (n=650) from 2006 to 2008 with hip or knee OA awaiting total joint arthroplasty (TJA) attended a hospital outpatient clinic for a prehabilitation assessment. All participants completed self-report (Lower Extremity Functional Scale [LEFS] and visual analogue scale for pain [VAS]) and functional performance measures (self-paced walk [SPW], timed stair, and timed up-and-go [TUG] tests). A subset of 28 participants with severe disability participated in a structured outpatient prehabilitation programme. Between-group differences were assessed via independent t-tests; paired Student's t-tests and Wilcoxon signed rank tests were used to compare changes in pain and function following the prehabilitation programme. A total of 28 individuals (16 female) with mean age 67 (SD 10) years and BMI 33 (8) kg/m(2) awaiting TJA (10 hips, 18 knees) participated in a prehabilitation programme of 9 (6) weeks' duration. Relative to baseline, there was significant improvement in LEFS score (mean change 7.6; 95% CI, 1.7-13.5; p=0.013), SPW (mean change 0.17 m/s; 95%CI, 0.07-0.26; p=0.001), TUG (mean change 4.2 s; 95%CI, 2.0-6.4; p<0.001), and stair test performance (mean change 3.8 s [SD 14.6]; p=0.005) following prehabilitation. This study presents preliminary evidence that prehabilitation improves physical function even in the most severely compromised patients with OA awaiting TJA.