diff --git a/engineapi/alembic/versions/040f2dfde5a5_request_id_decimal_column.py b/engineapi/alembic/versions/040f2dfde5a5_request_id_decimal_column.py
new file mode 100644
index 00000000..382f2074
--- /dev/null
+++ b/engineapi/alembic/versions/040f2dfde5a5_request_id_decimal_column.py
@@ -0,0 +1,75 @@
+"""Request ID decimal column
+
+Revision ID: 040f2dfde5a5
+Revises: b4257b10daaf
+Create Date: 2023-08-10 08:58:22.052336
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision = '040f2dfde5a5'
+down_revision = 'b4257b10daaf'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('call_requests', sa.Column('request_id', sa.DECIMAL(), nullable=True))
+    op.create_index(op.f('ix_call_requests_request_id'), 'call_requests', ['request_id'], unique=False)
+    op.create_unique_constraint(op.f('uq_call_requests_registered_contract_id'), 'call_requests', ['registered_contract_id', 'request_id'])
+
+    # Manual
+    # Fetch IDs of duplicates for 'dropper-v0.2.0' call_request_type and delete it
+    op.execute("""WITH Duplicates AS (
+    SELECT 
+        id,
+        registered_contract_id,
+        call_request_type_name,
+        parameters->'requestID' AS request_id,
+        created_at,
+        ROW_NUMBER() OVER (
+            PARTITION BY 
+                registered_contract_id,
+                call_request_type_name,
+                parameters->'requestID' 
+            ORDER BY created_at ASC
+        ) AS row_num
+    FROM call_requests
+    WHERE call_request_type_name = 'dropper-v0.2.0' 
+),
+DeleteDuplicates AS (
+SELECT id
+FROM 
+    Duplicates
+WHERE
+    row_num < (
+        SELECT COUNT(*) FROM Duplicates d2
+        WHERE d2.registered_contract_id = Duplicates.registered_contract_id
+        AND d2.call_request_type_name = Duplicates.call_request_type_name
+        AND d2.request_id = Duplicates.request_id
+    )
+)
+DELETE FROM call_requests WHERE id IN (SELECT id FROM DeleteDuplicates);""")
+               
+    # Fulfill not empty requestID values
+    op.execute("UPDATE call_requests SET request_id = CAST(parameters->>'requestID' AS DECIMAL) WHERE parameters->>'requestID' IS NOT NULL;")
+    # Fulfill raw types with random requestID
+    op.execute("UPDATE call_requests SET request_id = FLOOR(RANDOM()* 120500600 + 120400600) WHERE parameters->>'requestID' IS NULL;")
+    op.alter_column("call_requests", "request_id", nullable=False)
+
+    # Other
+    op.create_unique_constraint(op.f('uq_blockchains_id'), 'blockchains', ['id'])
+    op.create_unique_constraint(op.f('uq_call_request_types_name'), 'call_request_types', ['name'])
+    op.create_unique_constraint(op.f('uq_metatx_requesters_id'), 'metatx_requesters', ['id'])
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index(op.f('ix_call_requests_request_id'), table_name='call_requests')
+    op.drop_column('call_requests', 'request_id')
+    # ### end Alembic commands ###
diff --git a/engineapi/engineapi/contracts_actions.py b/engineapi/engineapi/contracts_actions.py
index e3039ff0..e5a632c1 100644
--- a/engineapi/engineapi/contracts_actions.py
+++ b/engineapi/engineapi/contracts_actions.py
@@ -65,6 +65,12 @@ class ContractAlreadyRegistered(Exception):
     pass
 
 
+class CallRequestAlreadyRegistered(Exception):
+    """
+    Raised when call request with same parameters registered.
+    """
+
+
 def parse_registered_contract_response(
     obj: Tuple[RegisteredContract, Blockchain]
 ) -> data.RegisteredContractResponse:
@@ -92,6 +98,7 @@ def parse_call_request_response(
         call_request_type=obj[0].call_request_type_name,
         caller=obj[0].caller,
         method=obj[0].method,
+        request_id=str(obj[0].request_id),
         parameters=obj[0].parameters,
         expires_at=obj[0].expires_at,
         created_at=obj[0].created_at,
@@ -112,7 +119,6 @@ def validate_method_and_params(
             )
         required_params = {
             "dropId",
-            "requestID",
             "blockDeadline",
             "amount",
             "signer",
@@ -397,6 +403,7 @@ def request_calls(
             metatx_requester_id=metatx_requester_id,
             caller=normalized_caller,
             method=specification.method,
+            request_id=specification.request_id,
             parameters=specification.parameters,
             expires_at=expires_at,
         )
@@ -405,6 +412,9 @@ def request_calls(
     # Insert the new rows into the database in a single transaction
     try:
         db_session.commit()
+    except IntegrityError as err:
+        db_session.rollback()
+        raise CallRequestAlreadyRegistered()
     except Exception as e:
         db_session.rollback()
         raise e
diff --git a/engineapi/engineapi/data.py b/engineapi/engineapi/data.py
index fe90dbf0..3c7bdd48 100644
--- a/engineapi/engineapi/data.py
+++ b/engineapi/engineapi/data.py
@@ -271,6 +271,7 @@ class CallSpecification(BaseModel):
     caller: str
     method: str
     call_request_type: str = "dropper-v0.2.0"
+    request_id: str
     parameters: Dict[str, Any]
 
     @validator("caller")
@@ -302,6 +303,7 @@ class CallRequestResponse(BaseModel):
     call_request_type: Optional[str] = None
     caller: str
     method: str
+    request_id: str
     parameters: Dict[str, Any]
     expires_at: Optional[datetime] = None
     created_at: datetime
diff --git a/engineapi/engineapi/models.py b/engineapi/engineapi/models.py
index 895cb136..36cc975d 100644
--- a/engineapi/engineapi/models.py
+++ b/engineapi/engineapi/models.py
@@ -1,6 +1,7 @@
 import uuid
 
 from sqlalchemy import (
+    DECIMAL,
     VARCHAR,
     BigInteger,
     Boolean,
@@ -8,15 +9,15 @@ from sqlalchemy import (
     DateTime,
     ForeignKey,
     Index,
+    Integer,
     MetaData,
     String,
     UniqueConstraint,
-    Integer,
 )
-from sqlalchemy.dialects.postgresql import JSONB, UUID, ARRAY
+from sqlalchemy.dialects.postgresql import JSONB, UUID
 from sqlalchemy.ext.compiler import compiles
-from sqlalchemy.orm import relationship
 from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import relationship
 from sqlalchemy.sql import and_, expression
 
 """
@@ -278,6 +279,12 @@ class RegisteredContract(Base):  # type: ignore
 
 class CallRequest(Base):
     __tablename__ = "call_requests"
+    __table_args__ = (
+        UniqueConstraint(
+            "registered_contract_id",
+            "request_id",
+        ),
+    )
 
     id = Column(
         UUID(as_uuid=True),
@@ -304,7 +311,7 @@ class CallRequest(Base):
 
     caller = Column(VARCHAR(256), nullable=False, index=True)
     method = Column(String, nullable=False, index=True)
-    # TODO(zomglings): Should we conditional indices on parameters depending on the contract type?
+    request_id = Column(DECIMAL, nullable=False, index=True)
     parameters = Column(JSONB, nullable=False)
 
     expires_at = Column(DateTime(timezone=True), nullable=True, index=True)
diff --git a/engineapi/engineapi/routes/metatx.py b/engineapi/engineapi/routes/metatx.py
index 1837a339..3af6bac9 100644
--- a/engineapi/engineapi/routes/metatx.py
+++ b/engineapi/engineapi/routes/metatx.py
@@ -382,6 +382,11 @@ async def create_requests(
             status_code=400,
             detail=f"Unacceptable call request required params specified, err: {err}",
         )
+    except contracts_actions.CallRequestAlreadyRegistered:
+        raise EngineHTTPException(
+            status_code=409,
+            detail="Call request with same request_id already registered",
+        )
     except Exception as err:
         logger.error(repr(err))
         raise EngineHTTPException(status_code=500)