The purpose of this study was to compare the effectiveness of mineral trioxide aggregate (MTA) and calcium hydroxide (CH) as pulp capping materials in humans by means of a meta-analysis.The PubMed, Cochrane Library, Embase, and Web of Knowledge databases were used in the literature search from their establishment date until December 7, 2014. Studies that met the inclusion criteria were accepted, and necessary information was extracted by 2 authors independently using a standardized form. The success rate, inflammatory response, and dentin bridge formation were evaluated.Thirteen studies met the inclusion criteria. There was no significant heterogeneity between studies, so a fixed-effects model was used. The MTA treatment groups showed a significantly higher success rate compared with CH-capped groups (randomized controlled trials: odds ratio [OR] = 2.26; 95% confidence interval [CI] = 1.33–3.85; P = .003; retrospective nonrandomized trials: OR = 2.88; 95% CI, 1.86–4.44; P < .00001). MTA was superior to CH in terms of the absence of an inflammatory response as well as dentin bridge formation, with the OR being 4.56 (95% CI, 2.65–7.83) and 3.56 (95% CI, 1.89–6.70), respectively.MTA has a higher success rate and results in less pulpal inflammatory response and more predictable hard dentin bridge formation than CH. MTA appears to be a suitable replacement of CH used for direct pulp capping.