Examples pertaining to re-transmission cyclic redundancy check (CRC) for polar coding incremental-redundancy hybrid automatic repeat request (IR-HARQ) are described. An apparatus (e.g., UE) encodes a plurality of information bits using a polar code to generate a polar code block (CB). The apparatus performs one or more transmissions of the polar CB using hybrid automatic repeat request (HARQ) by performing an initial transmission of the polar CB and performing a re-transmission of the polar CB with a re-transmission cyclic redundancy check (ReTX CRC).