Although much has been written recently on the cost-effectiveness of expanding malaria diagnosis, available information is scarce on a number of other important reasons why clinical diagnosis has been recommended for so long, especially among children living in high transmission settings. First, uncomplicated malaria can progress to severe or fatal illness within 24 to 48 hours of onset. Numerous care-seeking studies have demonstrated that caretakers seldom arrive at formal health facilities within 24 or 48 hours after the onset of uncomplicated febrile illness. If a diagnostic test imposes additional barriers—such as cost, time delay, or referral—requiring a positive parasitological diagnosis could put children whose cause of fever is malaria infection at greater risk of progressing to severe or fatal illness. Second, although the current approach based on clinical diagnosis appears to result in substantial over-treatment, it is still possible to demonstrate that children living in malaria transmission areas benefit from additional scheduled doses of antimalarial treatment, even when they are not ill. For example, a meta-analysis of six trials of sulfadoxine-pyrimethamine (SP) given to children at routine immunization visits demonstrated an average decrease of 30% in episodes of clinical malaria, 15% in anemia, and 24% in all-cause hospital admissions among children receiving SP compared to children who did not receive the drug at these visits. Finally, providers and clients may be inclined to disregard a negative blood slide or RDT, especially in situations where they have not identified an additional treatable cause of illness. Withholding antimalarial treatments from such children might adversely affect provider and client satisfaction and poor client satisfaction may reduce subsequent health facility utilization. It might also encourage disappointed clients to seek treatment in the private sector where a broad range of antimalarial drugs—most of them single drug treatments that contribute to the development of resistance and which are not recommended in the national treatment policy—can be obtained without diagnostic confirmation.