The work presents the data on the productive efficiency of water used for evapotranspiration by the sward of mountain grasslands. Mean grassland water productive efficiency for the vegetation period in the Małe Pieniny Mts. region fluctuates from 14.1 to 33.4 kg•ha-1•mm-1. The efficiency of water use under the discussed conditions is significantly influenced the amount of produced yield. Water was the least efficiently used by low-yielding sward. Water was the least effectively utilized by the low-yielding sward. Efficiency of water utilization by grasslands is growing with increasing yielding. Maintaining constant ground water level in the meadow habitats at the depth of 0.6m in the Pieniny region leads to a decrease in productive efficiency of water used for real evapotranspiration.