This kit enables the fixation and permeabilization of cells which is necessary for staining intracellular cytokines with fluorochrome-conjugated anti-cytokine antibodies. The kit provides two reagents, fixation/permeabilization solution and BD Perm/Wash™ Buffer. After cell fixation and permeabilization, the BD Perm/Wash™ Buffer is used to wash the cells and to dilute the anti-cytokine antibodies for staining.