The US held the largest share in the Japanese sorghum market for 20 years. However, in recent years Australia’s share of the same market has been constantly growing to claim the top position despite the fact that the US sorghum price is cheaper in that country. The ratio of US vs Australian sorghum prices in Japan during the last 20 years does not show too much variability, which seems to imply that the US sorghum has not lost price competitiveness in the Japanese market. Factors other than the price may be affecting the market share of the US sorghum in Japan. Therefore, our research objective is to confirm, using historical data and sound methodology, that grain quality differential might be the variable explaining the loss of US market share that country. This analysis will be helpful in terms of allowing the US sorghum producers to regain market share on the important Japanese market.