Genetic diversity in crop germplasm is an important resource for crop improvement, but information on genetic diversity is rare for Jerusalem artichoke, especially for traits related to water use efficiency. The objectives of this study were to investigate genetic variations for water use and water use efficiency in Jerusalem artichoke accessions and to identify superior genotypes for these characters under different water regimes. Forty Jerusalem artichoke accessions were arranged in a strip plot design with four replications for two years. Three strip plots represented three water regimes (W1 = 100%, W2 = 75% and W3 = 45% of crop water requirement). Data were recorded for tuber dry weight, biomass, relative water content, water use and water use efficiency. The effects of water regimes and Jerusalem artichoke accessions were significant for all characters. Genotypes contributed the largest portions for water use efficiency for biomass and tubers. These results documented genetic diversity for water use efficiency in Jerusalem artichoke. The genotypes with high water use efficiency for biomass were HEL 231, HEL 65 and JA102 x JA89(8). HEL 65 had high water use efficiency for tubers. These genotypes should be useful in future breeding programs for higher water use efficiency.