Greenhouse and laboratory research studied K and CI nutrition of four soybean [Glycine max(L) Merril] cultivars with differential resistance to Soybean Cyst Nematode (SCN,Heterodora glycinesIchinohe). The cultivars: Forrest (Group V, resistant to races 1 and 3), Bradley (Group VI, resistant to races 1, 3 and 4), Essex (Group V, susceptible), and Davis (Group VI, susceptible*) were used. Potassium treatments were zero K, K2SO4and KCI, and SCN treatment was zero and 500 eggs/100 g of previously sterilized soil. Single plants were grown for 30‐days in 400 g of soil in 3.5 cm pots maintained at 23°C. Plants were separated into roots and shoots for analysis. Post harvest SCN cyst counts were completed to evaluate cultivar‐K treatment effect on SCN population dynamics and treatment effects on root and shoot K, Ca, Mg and CI.