At the outbreak of the Russo-Japanese War in 1904, the traditionally close relationship between Imperial Germany and Tsarist Russia appeared as cordial as ever. Russia had an alliance with France but, except for its lucrative financial advantages for the Russians, this Dual Alliance remained largely an untested one vis-à-vis Germany. Less than a year after the conclusion of peace between Russia and Japan meaningful friendship between Russia and Germany ceased to exist. Within another year, Russia settled her major Asiatic differences with Great Britain, thus completing the process of isolating Germany diplomatically. The culminating period in this deterioration of Russo-German friendship occurred during the seven-month interval between the end of the Portsmouth Peace Conference in September 1905 and Germany's refusal to participate in the international loan to Russia in April 1906. This paper seeks to examine the causes of Russo-German estrangement within the framework of interrelated and often conflicting considerations of German Weltpolitik, Russian military defeats, the Revolution of 1905, and the international aspects of the Moroccan question.