The experiment was run at the Agricultural Experiment Farm, Grabów, operated by the Institute of Soil Science and Plant Cultivation – National Research Institute in Puławy in the years 2005–2007. The study comprised blue lupin varieties: cv. Graf, cv. Zeus (indeterminate type), cv. Sonet, cv. Boruta (determinate type). The experiment was arranged as a split-plot-split-block design with four replications and set up on a good wheat complex soil rated as crop production class IIIa. Amount and distribution of rainfall in each year had a large impact on morphological characters of blue lupin. Shortage of rain in the period of spring and summer negatively affected plant height and restricted leaf area.  Yields were to the largest extent dependent on the amount of rainfall in June, i.e. in the blooming period of the plant. Decrease in yield observed in years in which the weather was unfavourable to the production of blue lupin was due to reduced values of yield components, including, fi rst of all, number of pods per plant and number of seeds per plant since the 1000-seed weight was not altered signifi cantly. The indeterminate cultivars, Graf and Zeus, turned out to be less sensitive to periodical shortages of water in soil in comparison to the determinate cultivars Sonet and Boruta.