The aim of current study was to compare the standard methods for the determination tuber dry matter content (TDM) of diverse potato genotypes under various environmental conditions. Moreover, stability statistics were performed to identify stable genotypes with optimum TDM. TDM is considered as the main determinant of processed potato tuber quality. So, it is imperative to investigate rapid, practicable and reliable methods to measure TDM. A study was therefore, planned to compare three standard methods (Martin Lishman’s digital Potato hydrometer, moisture-drying on quartz seasand and oven-dry) for the determination of TDM among 189 diverse potato genotypes, grown under three environmental conditions (Hatay “standard water application”, Konya “standard water application” and Konya “drought” conditions), during the year 2018. ANOVA revealed highly significant differences (p<0.01) in all treatments among tests, checks and tests vs check genotypes. Environmental conditions significantly affect the TDM, while methods showed differential response within the tested environments. A strong correlation and high goodness of fit was observed between seasand and hydrometer methods. Oven-dry method showed weak “r” and R2 values with latter two methods. Wide applicability and reliability of seasand and hydrometer methods was also confirmed by stability analysis. Parametric stability methods such as bi and S2di identified stable genotypes that can serve as a useful resource for breeding of processing cultivars.