In recent years, US-China relations have become increasingly strained. This study identifies what the two countries perceive to be the major contentious issues in their political, economic and security relations. By comparing how these perceptions converge and diverge, the analysis results in a set of foundational discordances in Chinese and US perceptions: 1) Mutual distrust; 2) Support for an international rules-based system - but with different rules; 3) Competing ideologies; 4) Disagreement regarding the extent of China's global ambitions; 5) Contesting views regarding China's territory; and 6) Ambiguous perceptions of power. These discordances make it increasingly difficult for the two countries to mitigate tensions, as they often relate to issues that each side considers to be core parts of its national interests. While the US views China's advancements as a challenge to the current international system and its leading position, China perceives US actions as efforts to impede China's development, and ultimately also as a threat to the continued rule of the Communist Party. The implications of deteriorating US-China relations are global in scope, and may pressure other states to find a middle-way or ultimately choose sides in the struggle between the two countries.