Introduction of flow cytometric technique to the research on basophil activation has led to significant achievements in allergy diagnosis in vitro. Most of the studies employing the flow cytometry used CD63 as a marker of basophil activation and only some of them used CD203c. Recently discovered basophil activation markers, including CD164, opened new possibilities for solving majority of current diagnostic needs. Use of allergen-induced CD164 upregulation in diagnosis of pollen allergy has been validated, and this encourages to further studies on other diagnostic usefulness of this marker. There are some hopeful data indicating that it might be useful in diagnosis of allergy caused by variety of other allergens, including drug allergens. Although CD164 upregulation as a marker of basophil activation is a promising and powerful diagnostic tool, it still requires a lot of both basic research and comparative studies with older and well known markers, in order to select the best of them. A research on basophil CD164 upregulation caused by various stimuli offers a good possibility to increase our knowledge of basophil's involvement in allergic inflammation. Moreover, this might trigger a variety of pharmacological studies with known and new anti-inflammatory drugs in the future.