cAMP plays a pivotal role in control of cell movement, differentiation and response to stress in all phases of the Dictyostelium life cycle. The multitudinous functions of cAMP require precise spatial and temporal control of its production, degradation and detection. Many novel proteins have recently been identified that critically modulate the cAMP signal. We focus in this review on the properties and functions of the three adenylyl cyclases and the three cAMP-phosphodiesterases that are present in Dictyostelium, and the network of proteins that regulate the activity of these enzymes. We also briefly discuss the two modes of detection of cAMP.