Introduction Late (commenced 6 months to 4 years post-op) home-based progressive resistance training programs are proven to improve muscle strength and function after total hip replacement (THR). This study assessed whether early (commenced < 1 week post-op) HBPRT post-THR improves muscle mass, strength and function relative to routine physiotherapy rehabilitation (RPR) at up to 12 months follow up. Methods Prospective single blind randomized controlled study performed after ethical approval. 50 patients randomised to 6 week HBPRT (n=26) or RPR (n=24) postoperatively. Maximal voluntary contraction of the operated leg quadriceps in (MVCOLQ) in Newtons (N), sit to stands in 30 seconds (ST, number of repetitions), and the lean mass in grams of the operated leg (LM) were assessed preoperatively and at intervals up to 12 months postoperatively. Mixed model repeated measures ANOVA was used for statistical analysis. Results With loss to follow up, 35 patients; HBPRT n=20 (males n=9, females n=11) and RPR n=15 (males n=6, females n=9); were analyzed preoperatively with 26 patients (HBPRT n=13, RPR n=13) completing 12 month follow up. There was no effect in the mixed model repeated measures ANOVA for randomization into either HBPRT or RPR for MVCOLQ (F=0.065, p=0.800), ST (F=0.255, p=0.617) or LM (F=0.849, p=0.364). Statistically significant improvement over time was obtained for MCVOLQ (F=21.519, p=0.002) and ST (F=41.895, p=0.003) but LM remained unchanged (F=0.003, p=0.954). Conclusions Early HBPRT has no additional benefit when compared to RPR post-THR. Additional functional gain post-THR is possible with HBPRT only when it is applied late.