Protoporphyrinogen IX is an organic chemical compound which is produced along the synthesis of porphyrins, a class of critical biochemicals that include hemoglobin and chlorophyll.

The compound is a porphyrinogen, meaning that it has a non-aromatic hexahydroporphine core, which will be oxidized to a porphine core in later stages of the heme synthesis.

In coproporphyrinogen III, the substituents on the pyrrole rings have the arrangement MP-MP-MP-PM, where M and P are methyl and propionic acid, respectively.

In protoporphyrinogen IX, the sequence becomes MV-MV-MP-PM, where V is vinyl.

By the action of protoporphyrinogen oxidase, protoporphyrinogen IX is later converted into protoporphyrin IX, the first colored tetrapyrrole in the biosynthesis of hemes.