Abstract: Background and Objective: Blast is one of the most destructive diseases of rice worldwide. Use of blast resistant varieties is considered the most effective and economical way of controlling the disease. Local cultivars of upland rice are potential sources of blast resistance, especially for development of superior red and black rice varieties. The objectives of this study were: (1) To assess blast resistance levels of red and black upland rice local cultivars against four dominant races of Pyricularia grisea (P. grisea) in Indonesia and (2) To identify red and black upland rice cultivars having resistance to both single and multiple races of P. grisea. Materials and Methods: The study was conducted in two sites, i.e., in the Glasshouse of Faculty of Agriculture, University of Nusa Cendana and the Glasshouse of Muara Research Station of Indonesian Center for Rice Research during August-November, 2015. A completely randomized design was employed with two-factor treatments, i.e., rice genotype and P. grisea race. Forty two rice genotypes (39 local cultivars and three check varieties) were inoculated with four races of P. grisea, each was five replicates. The variables observed were infection period and disease severity, each was subjected to analysis of variance, followed by DMRT post hoc test. The disease severity was used for classification of blast resistance levels of tested rice genotypes. Results: There was a highly significant interaction effect of rice genotype by P. grisea race on either infection period or disease severity. The tested rice genotypes were classified into six resistance levels for races 033 and 073 inoculations and five resistance levels for races 133 and 173 inoculations. Conclusion: Twenty three local genotypes exhibited blast resistant reaction (highly resistant+resistant), of which 11 genotypes were resistant to single race and 12 genotypes were resistant to multiple races of P. grisea.