A study comparing five different cAMP detection technologies in terms of sensitivity, robustness, and feasibility for HTS is presented. In this report, the following methods are described: a nonhomogeneous DELFIA, and the homogeneous methods based on time-resolved fluorescence (HTRF), luminescent singlet oxygen channeling or ALPHAScreen, FP, and high-affinity enzyme complementation. DELFIA had the highest sensitivity, whereas ALPHAScreen and HTRF shared several advantages, including high sensitivity, broad dynamic range, and minimal reagent addition steps. For G(s)-coupled antagonist screens, we found HTRF and ALPHAScreen the more sensitive and HTS-compatible techniques.