What criteria can be used to diagnose malaria in health centers located in endemic areas? Can an algorithm be developed for management of fever episodes? What parameters should be used to assess the morbidity of malaria for public health surveys or for studies to determine the efficacy insecticide-impregnated bednets, drug prophylaxis protocols, or anti-malarial vaccinations? Finding a useful definition for malaria attack is a perennial problem that becomes more difficult to resolve as the transmission rate and immunity level of the population increases. This review presents the fundamental aspects of diagnosing malaria. The choice of diagnostic technique requires knowledge of physiopathological, epidemiological, and clinical features. There is no single method. It depends on the circumstances, epidemiological context, available facilities, and goals. Diagnosis for treatment is one thing. Diagnosis for evaluation is another. In addition to discussing these concepts, this article provides references from the recent literature and up-to-date information needed to deal with the problem of diagnosing malaria attacks in endemic areas.