CO 170 denial code

Claim adjustment reason code 170. Often reported as CO 170.

Denied for this type of provider

Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated Nov 11, 2026.

What 170 means

Payment was refused because the payer does not pay this service when your provider type performs or bills it.

The payer restricts who can be paid for this service. Your provider type, for example a certain kind of practitioner or supplier, is not one it pays for this code.

The remittance may cite a policy reference. Check that your provider type is set up correctly with the payer, because an enrollment error can trigger this.

Group codes seen with 170

On a remittance, 170 comes after a group code. These are the ones it is most often reported with:

• CO 170 (Contractual Obligation): The provider's side of the ledger. The reduction comes from the payer contract or a rule the provider has to follow, and the patient normally cannot be billed for it.

The payer chooses the group code for each adjustment, so the same reason code can appear with another group code on your remittance. Read the two together. More about group codes.

Common causes

• The service is limited to provider types that do not include yours.
• Your provider type or taxonomy is recorded wrong in the payer's file.
• The claim listed the wrong rendering or billing provider.

What to do next

1. Check the remittance for a policy reference and read the provider type rules.
2. Confirm your enrollment, provider type and taxonomy with the payer.
3. Correct and resubmit if the wrong provider was listed on the claim.

Related codes

• 171 (reason code) Denied for provider type in this facility
• 172 (reason code) Adjusted for provider specialty
• 185 (reason code) Rendering provider not eligible