Rhizoctonia crown and brace root rot of maize caused by Rhizoctonia solani AG2-2IIIB is spreading and may affect crop production. Breeding of maize with resistance to R. solani AG2-2IIIB seems to be the most promising way to control the disease. The objectives of this study were (i) to develop a greenhouse screening method to assess resistance of maize genotypes to R. solani, and (ii) to screen 55 maize cultivars or breeding lines for resistance to R. solani. In a pot experiment, plants were inoculated after sowing with mycelial suspensions of a highly aggressive isolate of R. solani AG2-2IIIB. Root symptoms were recorded assessing the percentage of root rot. Significant differences between three standard cultivars became obvious three weeks past inoculation. The same ranking of the standards was obtained in four experiments. In two experiments, 26 hybrids and 29 inbred lines were tested for resistance to R. solani. Differences in disease severity were apparent between tested maize genotypes as well as between the standards we used. In comparison to all other genotypes, the roots of one line and two hybrids showed only few symptoms. The inbred lines were more susceptible than the hybrids. Disease expression was significantly related to the reduction of plant fresh weight. Thus, the described inoculation method is a valuable tool to screen maize genotypes easily, reliably and fast for resistance to R. solani AG2-2IIIB in the greenhouse.