This study introduces the 2005 life cycle data for nickel in 50 countries and presents a comparative analysis of the 2000 and 2005 nickel and stainless steel cycles for these countries. The life cycles of the two metals are linked by nickel's role as a major alloying element in most stainless steels. Between 2000 and 2005, the global use of both metals grew, driven by China's extraordinary growth and despite the fact that many industrialized countries decreased their metal use during that time. China's and India's growth of stainless steel use was greater than that of nickel use, a result of price-driven substitution away from nickel-containing stainless steels. The intensity of use (IU) in industrialized countries is about 30 to 50 kilograms (kg) nickel/million U.S. dollars (USD), and 300 to 500 kg stainless steel/million USD. High-income countries decreased their IU of both metals between 2000 and 2005, while low- and medium-income countries increased their IU of stainless steel. At the per capita level, average industrialized countries use about 1 kg of nickel and 11 kg of stainless steel. Were China's and India's projected urban areas in 2025 to use similar amounts of the two metals, they alone would require the equivalent of global nickel production in 2000, and 200% of the world's stainless steel production in 2005. In China, substantial nickel and stainless steel end-of-life flows will arise between 2015 and 2020, and efficient collection and separation systems should be prepared now to maximize the potential environmental and resource benefits of recycling.