Multiple successive pressure blottings of a single agarose isoelectric focusing gel were performed on normal and CNBr-activated nitrocellulose (NC) filters. The results obtained by multiple successive 10s immunoprints were compared to those obtained by a single 10 min immunoprint. To quantify the transfer efficiency of these techniques, a defined amount of radioactive material was separated by isoelectric focusing on agarose gel. After separation and pressure blottings of the gel the NC filters were submitted to autoradiography. The amount of radioactive material bound to the NC filters was determined by scintillation technique. The single 10 min pressure blot was more efficient than each of the multiple successive 10s prints. However, the latter procedure allowed equal resolution and resulted in a higher recovery of total radioactivity than the single immunoprint technique. The aim of this paper is to show how to obtain highly reproducible prints of electrophoretic patterns in an agarose gel of heterogeneous samples when accurate multiple immunodetections are to be performed. This technique was tested to characterize the grass pollen specific immunoglobulin classes and subclasses from an allergic patient.