Imported malaria is an increasing problem in many countries. The objective of this study was to prospectively evaluate the diagnosis and treatment of imported malaria cases identified by active surveillance. Microscopic diagnosis at the community level was also compared to reference microscopic and blinded molecular diagnostic methods. Most travelers who acquire malaria had sought pretravel advice from a physician; however, only 11% used recommended chemoprophylaxis and only 17% used insect protection measures. The diagnosis of malaria was initially missed in 59% of cases. Community-based microscopic diagnosis provided incorrect species identification in 64% of cases. After presentation, the average delay before treatment was 7.6 days for falciparum malaria and 5.1 days for vivax malaria. Overall, 7.5% of Plasmodium falciparum-infected patients developed severe malaria, and in 11% of all cases therapy failed. Patients who present to a center without expertise in tropical medicine receive suboptimal treatment. Improvements in recognition, diagnosis, and treatment of malaria are essential to prevent morbidity and death among travelers.