Inhaled glucocorticoids play an indispensable role in the therapy of asthma. Development of new compounds was initially directed to increase the potency of the individual corticosteroid; thereafter, pharmacokinetic characteristics were modified to reduce unwanted systemic effects. Target of the present development is to attain compounds with the most favorable risk-to-benefit ratios. Since then, there has been substantial discussion about how to rank and weigh the different glucocorticoids. This article provides an evaluation of the relevant clinical studies published between May 2001 and June 2002, identifying the main determinants of the therapeutic value of inhaled glucocorticoids.