The aim of this study was to investigate the fit of acrylic maxillary denture bases processed by the methods of microwave, quick-wet-heat, slow-wet-heat, and self curing. Forty stone-casts were obtained using a mould of an undercut-free acrylic resin master cast of an edentulous maxilla. Standard acrylic replicas patterns sealed on casts and randomized to four groups (10 in each) were used to make denture bases using different processing methods for each of the four groups. The resultant discrepancy of fit between the denture base and the casts were measured using a silicone wafer. Varying fit discrepancies both within and between denture base groups was observed. The proportional fit-loss in the palatal region was significantly greater than the sulcular areas for all materials tested (p < 0.05). The fit-loss observed was greater in microwave-cured bases than for other materials examined. Careful selection of appropriate denture base materials and processing technique is important when providing complete dentures for edentulous patients.