This field experiment was conducted for two years during kharif season of 2002-03 and 2003-2004 at Agricultural Research Station Rajasthan Agricultural University, Bikaner (Rajasthan) situated in Hyper Arid Partially Irrigated Western Plain zone of Rajasthan-India. It is situated at 28.01„a North latitude and 73.22„a East longitudes at an elevation of 234.70 m above the mean sea level. Chlorosis had developed 35 days after sowing in peanut under simulated conditions through irrigating crops in highly calcareous soils. In order to ascertain whether the chlorosis was due to iron deficiency the treatments of foliar application of (1) 0.5% ferrous sulphate (2) 1.0% ferrous sulphate (3) 0.5% ferrous sulphate+0.1% citric acid (4) 1.0% ferrous sulphate +0.1% citric acid (5) 0.5 % citric acid only were applied, besides the treatment of control (spray of distilled water). Results revealed that treatments of 1.0 % ferrous sulphate + 0.1% citric acid significantly increased pod and haulm yield by about two fold through significantly increasing chlorophyll and active iron contents in the leaves by about three to four folds over control. The treatment of 0.1% citric acid only was also equally effective in curing iron chlorosis over control. The chlorosis in peanut grown on calcareous soils was due to inactivation of iron in the plant and can be cured by foliar sprays of soluble salts of iron. (Key words: Chlorosis, foliar spray, ferrous sulphate, acid, ferric citrate, and groundnut)