Because of the worldwide engagement of the German armed forces, tropical diseases may come to the attention of their medical services. In particular, acquired malarial infections, which sometimes become symptomatic only months or even years after soldiers return from military operations, need to be addressed. Other forces, such as the British, U.S., Australian, and Italian armed forces, reported cases of vivax malaria up to approximately 20 months after soldiers returned from military operations. The importance of a sound history and rapid diagnosis, leading to appropriate treatment, is emphasized in this case report of a 27-year-old German soldier who reported for sick call in his unit complaining of a flu-like illness, which later proved to be vivax malaria. The special parasitological features of Plasmodium vivax infection are discussed.