Nitrite, salt, seasonings and other ingredients are used for the curing to give unique color, flavor and texture to the meat products. Sodium or potassium nitrite is incorporated into the processed meats to provide desirable meaty flavor, prevent warmed-over flavor, develop a bright reddish pink color and inhibit the microbial growth, particularly for out-growth of Clostridium botulinum spores. Sodium or potassium nitrate can also be used to cure the processed meats. However, nitrate has to be reduced to nitrite by the microorganisms to be effective for curing and mostly used for the slow-cured products including some fermented sausages and country style hams. The safety of nitrite and nitrate used for meat curing was questioned in the 1970s due to their potential to form carcinogenic nitrosamines in the stomach following the ingestion. Conversely, some potential health benefits were also attributed to both nitrite and nitrate in the recent studies since both compounds contribute to nitric oxide production in human body. Nitric oxide produced directly from nitrite has a significant effect on cardiovascular health by controlling blood flow in the cardiac muscle. Thus, the continuing controversy regarding human health concerns from nitrite and nitrate consumption in the diet are evaluated and discussed in this chapter.