Existance of genotype × environment interaction effects are constraints in evaluation and release of new cultivars. In order to evaluate new high-yielding promising lines and assess their yield stability, an experiment was conducted with ten promising genotypes of rice and two control variety (Shiroudi and Fajr) in two regions of Mazandaran (Deputy of Rice Research Institute in Amol and Ghavdasht Rice Research Station in Babol) under randomized complete block design with four replications during two years (2012-2013). Simple Analysis of variance indicated significant differences among the genotypes for all traits in two location. [Combined ANOVA was also performed following Bartlett test (for uniformity of error variances)]. Combined ANOVA was performed according to the homogeneity of experimental error. Results showed significant differences among the genotypes and reflect genetic differences between genotypes. Genotypes 3, 4, 5, 6 and 9 produced higher yields, with 5.8, 6.2, 6.3, 5.8 and 6.2 ton per hectare, respectively. Genotypes 7 and 6 showed highest harvest indices with 0.57 and 0.54, respectively. Genotype 6 due to its high harvest index and, a high percentage of filled seeds (%78 in group a) and its high yield, was selected as the best genotype.