Statement of problem: Studies assessing the trueness and tissue surface adaptation of computer-aided design and computer-aided manufacturing (CAD-CAM) mandibular complete denture bases fabricated using digital light processing (DLP) are lacking. Purpose: The purpose of this in vitro study was to evaluate the trueness of DLP–generated denture bases and to compare the tissue surface adaptation of DLP with milling and pack and press. Material and methods: The mandibular denture bases were virtually designed on a reference cast and were fabricated using DLP. Their intaglio surfaces were scanned and superimposed on the reference CAD denture base to evaluate the trueness. The reference cast was duplicated to create 10 identical master casts that were scanned to design 10 virtual denture bases. Twenty denture bases were fabricated with DLP and milling (10 specimens per technique). In addition, 10 denture bases were fabricated with the pack and press technique. The intaglio surfaces of the denture bases were scanned and superimposed on the corresponding master casts to compare tissue surface adaptation among the 3 techniques. The Mann-Whitney test and Kruskal-Wallis analysis of variance (α=.05) were used for statistical analyses. Results: For trueness, the milled denture base was better than the DLP denture base (P<.001). However, no statistically significant difference was detected with respect to tissue surface adaptation of the denture base, regardless of the fabrication technique (P>.05). The DLP denture base showed comparable tissue surface adaptation with the milled base, one with a small interquartile range. Conclusions: The intaglio surfaces of DLP and milled denture bases corresponded within a 100-μm accuracy compared with the master cast. Although the DLP denture base exhibited tissue compression on the ridge crest, it showed comparable tissue adaptation to the milled denture base.