diff --git a/cardano-api/internal/Cardano/Api/ProtocolParameters.hs b/cardano-api/internal/Cardano/Api/ProtocolParameters.hs
index 767e08a613..573dcb94fc 100644
--- a/cardano-api/internal/Cardano/Api/ProtocolParameters.hs
+++ b/cardano-api/internal/Cardano/Api/ProtocolParameters.hs
@@ -175,8 +175,7 @@ instance IsShelleyBasedEra era => Eq (LedgerProtocolParameters era) where
     shelleyBasedEraConstraints (shelleyBasedEra @era)
       $ a == b
 
--- TODO: Conway era - remove me when we begin relying on the JSON
--- instances of Ledger.PParams
+{-# DEPRECATED convertToLedgerProtocolParameters "Use the ledger's PParams (from module Cardano.Api.Ledger) type instead of ProtocolParameters." #-}
 convertToLedgerProtocolParameters
   :: ShelleyBasedEra era
   -> ProtocolParameters
@@ -465,6 +464,7 @@ createIntroducedInBabbagePParams w (IntroducedInBabbagePParams coinsPerUTxOByte)
 --
 -- There are also parameters fixed in the Genesis file. See 'GenesisParameters'.
 --
+{-# DEPRECATED ProtocolParameters "Use the ledger's PParams (from module Cardano.Api.Ledger) type instead of ProtocolParameters" #-}
 data ProtocolParameters =
      ProtocolParameters {
 
@@ -1669,6 +1669,7 @@ toConwayPParams = toBabbagePParams
 -- Conversion functions: protocol parameters from ledger types
 --
 
+{-# DEPRECATED fromLedgerPParams "Use the ledger's PParams (from module Cardano.Api.Ledger) type instead of ProtocolParameters." #-}
 fromLedgerPParams
   :: ShelleyBasedEra era
   -> Ledger.PParams (ShelleyLedgerEra era)
@@ -1681,6 +1682,7 @@ fromLedgerPParams ShelleyBasedEraBabbage = fromBabbagePParams
 fromLedgerPParams ShelleyBasedEraConway  = fromConwayPParams
 
 
+{-# DEPRECATED fromShelleyCommonPParams "Use the ledger's PParams (from module Cardano.Api.Ledger) type instead of ProtocolParameters." #-}
 fromShelleyCommonPParams :: EraPParams ledgerera
                          => PParams ledgerera
                          -> ProtocolParameters
@@ -1714,6 +1716,7 @@ fromShelleyCommonPParams pp =
     , protocolParamMinUTxOValue        = Nothing -- Obsolete from Alonzo onwards
     }
 
+{-# DEPRECATED fromShelleyPParams "Use the ledger's PParams (from module Cardano.Api.Ledger) type instead of ProtocolParameters." #-}
 fromShelleyPParams :: ( EraPParams ledgerera
                       , Ledger.AtMostEra Ledger.MaryEra ledgerera
                       , Ledger.AtMostEra Ledger.AlonzoEra ledgerera
@@ -1728,6 +1731,7 @@ fromShelleyPParams pp =
     }
 
 
+{-# DEPRECATED fromAlonzoPParams "Use the ledger's PParams (from module Cardano.Api.Ledger) type instead of ProtocolParameters." #-}
 fromAlonzoPParams :: AlonzoEraPParams ledgerera
                         => PParams ledgerera
                         -> ProtocolParameters
@@ -1743,6 +1747,7 @@ fromAlonzoPParams pp =
     , protocolParamMaxCollateralInputs = Just $ pp ^. ppMaxCollateralInputsL
     }
 
+{-# DEPRECATED fromExactlyAlonzoPParams "Use the ledger's PParams (from module Cardano.Api.Ledger) type instead of ProtocolParameters." #-}
 fromExactlyAlonzoPParams :: (AlonzoEraPParams ledgerera, Ledger.ExactEra Ledger.AlonzoEra ledgerera)
                         => PParams ledgerera
                         -> ProtocolParameters
@@ -1751,6 +1756,7 @@ fromExactlyAlonzoPParams pp =
       protocolParamUTxOCostPerByte = Just . unCoinPerWord $ pp ^. ppCoinsPerUTxOWordL
   }
 
+{-# DEPRECATED fromBabbagePParams "Use the ledger's PParams (from module Cardano.Api.Ledger) type instead of ProtocolParameters." #-}
 fromBabbagePParams :: BabbageEraPParams ledgerera
                    => PParams ledgerera
                    -> ProtocolParameters
@@ -1760,11 +1766,13 @@ fromBabbagePParams pp =
   , protocolParamDecentralization = Nothing
   }
 
+{-# DEPRECATED fromConwayPParams "Use the ledger's PParams (from module Cardano.Api.Ledger) type instead of ProtocolParameters." #-}
 fromConwayPParams :: BabbageEraPParams ledgerera
                   => PParams ledgerera
                   -> ProtocolParameters
 fromConwayPParams = fromBabbagePParams
 
+{-# DEPRECATED checkProtocolParameters "Use the ledger's PParams (from module Cardano.Api.Ledger) type instead of ProtocolParameters. PParams natively enforce these checks." #-}
 checkProtocolParameters :: ()
   => ShelleyBasedEra era
   -> ProtocolParameters
diff --git a/cardano-api/test/cardano-api-golden/Test/Golden/Cardano/Api/ProtocolParameters.hs b/cardano-api/test/cardano-api-golden/Test/Golden/Cardano/Api/ProtocolParameters.hs
index 54f720b692..d2309136b1 100644
--- a/cardano-api/test/cardano-api-golden/Test/Golden/Cardano/Api/ProtocolParameters.hs
+++ b/cardano-api/test/cardano-api-golden/Test/Golden/Cardano/Api/ProtocolParameters.hs
@@ -3,6 +3,9 @@
 {-# LANGUAGE NumericUnderscores #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 
+-- TODO remove me when ProtocolParameters is deleted
+{-# OPTIONS_GHC -Wno-deprecations #-}
+
 module Test.Golden.Cardano.Api.ProtocolParameters
   ( test_golden_ProtocolParameters
   , test_golden_ProtocolParameters_to_PParams
diff --git a/cardano-api/test/cardano-api-test/Test/Cardano/Api/ProtocolParameters.hs b/cardano-api/test/cardano-api-test/Test/Cardano/Api/ProtocolParameters.hs
index 8f566ce0a7..f93a1ec447 100644
--- a/cardano-api/test/cardano-api-test/Test/Cardano/Api/ProtocolParameters.hs
+++ b/cardano-api/test/cardano-api-test/Test/Cardano/Api/ProtocolParameters.hs
@@ -3,6 +3,9 @@
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TypeFamilies #-}
 
+-- TODO remove me when ProtocolParameters is deleted
+{-# OPTIONS_GHC -Wno-deprecations #-}
+
 module Test.Cardano.Api.ProtocolParameters
   ( tests
   ) where