Induced mutagenesis in crop plants has created avenues for improving desirable genetic changes without altering the unique genetic background of the promising cultivars. A study was carried out to find the efficiency and effectiveness of 0.2% Ethyl Methane Sulfonate (EMS) mutagen on four popular but tall local aromatic rice landraces, Kalikati, Basumati, Gangabali and Karpurajeera by treating the calli initiated from their mature embryos for three different durations (2 hours, 4 hours and 6 hours). A reduced shoot regeneration efficiency was witnessed in Kalikati and Basumati (59.54% and 61.10% reduced respectively) while it increased in Gangabali and Karpurajeera (23.32% and 29.76 % increased respectively) with increasing treatment duration, compared to control. Among the four types of chlorophyll mutants observed, albina were most frequent in all the genotypes except Basumati, where virdis mutants followed by albina were highest whereas, in Kalikati, chlorina mutants were followed by albina in high frequency. In general, mutagenic effectiveness and efficiency were reduced with an increase in the duration of treatment in all the genotypes except in Basumati and Karpurajeera where mutagenic efficiency was highest at mid-treatment duration (4 hours). Mutation rate of 10.68 observed in Basumati was the highest among the genotypes indicated high mutagenic effect on the calli of this aromatic rice landrace. Genotypic differences in frequency of mutants, effectiveness and efficiency of the mutagen on the aromatic rice genotypes were clearly evident. This research will be useful in mutation breeding programmes, involving economically important crops, within a limited time and space.