Russian wildrye [Psathyrostachys juncea Nevski] is potentially useful as a cool-season forage grass for the southern Great Plains. Our objective was to determine the effect of acidic and limed soils on seedling growth of tetraploid and diploid Russian wildrye germplasm. Seedlings of Mandan R1983 and Tetra-1 (tetraploids), as well as ‘Bozoisky Select’ and ‘Mankota’ (diploids), were grown in limed and nonlimed acidic sand, sandy loam, and silt loam soils in the greenhouse at Ardmore, OK. Seedlings were harvested following approximately 60 d of growth in soil. Root-bound Al was extracted with a solution of 0.5 M citric acid. Regardless of soil type, seedling shoots grew significantly (P < 0.05) larger because of lime application, averaging 13.1 cm taller and 100% heavier for limed versus nonlimed acidic soils. Tiller number, root length, and root weight also increased with lime application, though not as consistently. Root-bound Al did not differ between tetraploids and diploids. In most cases, tetraploids and diploids had an equally favorable response to liming, indicating that Russian wildrye seedlings are susceptible to soil acidity regardless of ploidy level. Because of consistency of response and ease of measurement, seedling shoot weight should be useful for screening Russian wildrye germplasm for possible tolerance to soil acidity. Russian wildrye cultivars with improved seedling tolerance to acidic soils, which occur extensively in the southern Great Plains, might well be needed.