SUMMARY:Leukocyte-endothelial cell interactions have a pivotal role in immune responses. In our study Ten adult wistar albino rats weighing 180-200 g were used to obtain tissue samples. The animals were sacrificed by decapitation under ether anesthesia. The lymph nodes of the animals were then quickly removed. Specimens were immersed in the zinc iodide-osmium tetroxide (ZIO) solutation by Niebauer et al. (1969) and kept in the dark for 2 hours in this solution from temperature for fixation/staining. Samples were processed according to routine plastic embedding tecnique. Semithin sections of 1µm thick were cut and stained with methilene blueazure II for light microscopic examination. We used zinc iodide-osmium tetroxide staining tecnique to distinguish endothelial cell from leukocytes.Present data supports the understanding of this unique relationship as documented by figures.