We designed a 48-well chemotaxis chamber to minimize manipulation time and amount of material required by the larger blindwell or Boyden chemotaxis chamber. Cell and chemoattractant dose-response curves showed that results were comparable to our better than those obtained with blindwell chambers. The volume of chemoattractant per well is 25 microliter; the number of cells can be as low as 10,000. The time needed for setting up this multiwell unit and for staining the membrane filter sheet is negligible. Combined with the use of an image analyzer to count the number of migrated cells, the method is suitable for clinical research on the functional state of monocytes in large groups of patients.