Much information has been obtained regarding how white cells are recruited in the microcirculation to sites of inflammation. In this review we summarize the leukocyte recruitment cascade, highlighting the molecular mechanisms that underlie each of the major steps. Major emphasis is placed on the selectins and integrins and their role in rolling and adhesion. Intraluminal crawling and emigration are also briefly discussed. In addition, we summarize some of the data that implicate these molecules in eosinophil recruitment in animal models of asthma and in lymphocyte recruitment in skin contact sensitivity. There is a growing body of evidence to suggest that leukocyte recruitment could be used as an effective means for future therapeutics, and some of these issues are also raised.