Background: Soil calcareousness is the major problem in arid and semi arid regions globally since lime induced chlorosis lead to the deficiency of many essential plant nutrients which in turn resulted in reduced growth and yield loss of many crops. To explore the effects of various concentrations of calcium carbonate (CaCO3) on seed germination and seedling growth of groundnut genotypes and to identify CaCO3 stress tolerant and sensitive groundnut genotypes. Methods: The seed germination and seedling growth of ten groundnut genotypes (CO 6, CO 7, TMV 2, TMV 10, TMV 13, TMV 14, VRI 7, VRI 8, ALR 2 and BSR 2) was investigated with CaCO3 concentrations ranging from 1 to 100 mM L-1 for a period of 14 days. Result: The genotypes VRI 8 and TMV 10 showed higher seed germination and seedling growth even at higher CaCO3 concentration (upto 20 mM L-1) and considered as tolerant genotypes. Whereas TMV 2 and VRI 7 exhibited drastic reduction even at 1 mM L-1 and confirms their susceptibility to CaCO3 stress. Higher concentrations of CaCO3 in the growing medium greatly decreased the germination rate, germination index and vitality index but the impact differs with potentials of genotypes studied. [ABSTRACT FROM AUTHOR]