Zinc deficiency is most prevalent in alkaline/calcareous, inherently low organic carbon, heavily limed, light textured, salt prone, and waterlogged soils. In this review the diagnosis and correction of Zn deficiency in several important crops in a wide range of soils has been discussed. Crop yield increases up to 120% in wheat, 48% in rice, 50% in cotton, 18% in maize, 22% in potato, 30% in alfalfa, 50% in soybean and 26% in citrus orchards have been reported with application of Zn by using appropriate rates, methods (soil or foliar) and sources (such as ZnSO4). Critical soil Zn concentration range for most crops has been reported between 0.5-2.0 mg kg-1for DTPA and 0.53.0 mg kg-1 for Mehlich-1. In general, soil application of 5-11 kg Zn ha-1 is recommended for 3-4 crop seasons to sustain crop production. In the past, the focus of agronomists and policy makers has been on crop production, rather than crop nutritional quality. This phenomenon contributed to Zn malnutrition in humans. The two most common approaches to overcome Zn deficiency in humans are nutraceutical, and bio-fortification, which have been addressed in detail.