This paper describes a simple method for carrying out dot-blot immunoassays simultaneously with a large number of different sera. No dot-blot manifold is necessary, only a modified 96-well flat-bottom microtiter plate. This apparatus is re-usable, inexpensive and especially suited for field testing of patient sera in serodiagnostic assays. One application of this technique, to the serodiagnosis of visceral leishmaniasis on a pure parasite protein, is demonstrated.