If the tools for the control of transmission are not available, the application of seroepidemiologic methods, as an exercise in the tropics, just in order to assess the magnitude of the problem of malaria transmission, should be restricted. Application of seroepidemiologic methods in connection with control operations seems valuable. They can provide new and basic information. It is very unlikely that in control schemes, the assessment of incidence of fresh parasitemias is better, easier, or more accurate than in a serological survey. There seems to be no great interest in refining our methodology for seroepidemiologic techniques. Renewed interest will be prompted by reliable and effective control operations. This may be in the form of a vaccine, a new drug or another insecticide, but it must be within the economic limits of the malarious country.