The authors conducted a systematic review and meta-analysis to determine if Core Decompression (CD) with Bone Marrow Stem Cells (BMSC) is more effective in treating Osteonecrosis of the Femoral Head (ONFH) compared to CD. Authors used Cochrane Library, EMBASE, PubMed, Web of Science, and hand-searched references through January 2020, identifying relevant randomized controlled trials (RCTs). Risk of bias was assessed with Cochrane's handbook. Fifty-four abstracts were screened, and eight RCTs (five at high and three at unclear risk of bias) with 432 patients were included. Meta-analyses found statistically significant improvement in Harris Hip Score (HHS) at 12 months (Difference in Means [DM]=10.065;95% Confidence Interval [CI]=4.509 to 15.622; p<0.001) and pain intensity at 24 months (DM=-7.364;95% CI=-12.113 to -2.615;p=0.002) in CD+BMSC group compared to CD alone although these results may not be clinically significant. Risk of Total Hip Replacement (THR) in patients receiving CD+BMSC was 33.4% lower than in CD group though not significant (RR=0.666; 95% CI=0.355 to 1.250;p=0.206). Though meta-analyses found the addition of BMSC to CD significantly improves clinical outcomes (HHS and pain intensity) compared to CD only, evidence was of moderate/low quality due to high risk of bias, imprecision, and small sample sizes. Further research is needed to confirm the results.