DFT calculations on palladium(II) methyl complexes incorporating P/N ligands demonstrate that CO activation in the presence of competing ligands, such as CH3CN or C2H4, occurs through an associative mechanism involving CO/ligand exchange, followed by migratory insertion of CO into the PdMe bond. Recent investigations into the PdII coordination of CO and C2H4 and their subsequent insertion into the PdMe bonds of complexes of the type [PdMe(iminophosphine)(NCMe)]+ are reported.