Three-component coupling reaction of conjugated dienes, thiols, and carbon monoxide affords an atom-economical thiocarbonylation of the dienes to give β,γ-unsatd. thioesters as the sole products. A catalyst system based on [Pd(OAc)2] and Ph3P showed excellent catalytic activity. The thiocarbonylation was performed under an atm. of carbon monoxide (400 psi) at 110 °C in CH2Cl2 for 60 h. A wide variety of thioesters were synthesized in good to excellent yields from easily accessible starting materials. The reaction is believed to proceed via a η3-allylpalladium intermediate. The thiocarbonylation, which is applicable to a wide variety of conjugated dienes, occurs in high regioselectivity, the latter dependent on the steric characteristics and stability of the η3-allylpalladium complex.