diff --git a/snuba/web/rpc/proto_visitor.py b/snuba/web/rpc/proto_visitor.py
index 17571557da..a87098307e 100644
--- a/snuba/web/rpc/proto_visitor.py
+++ b/snuba/web/rpc/proto_visitor.py
@@ -59,6 +59,10 @@ def accept(self, visitor: ProtoVisitor) -> None:
 class AggregationComparisonFilterWrapper(ProtoWrapper[AggregationComparisonFilter]):
     def accept(self, visitor: ProtoVisitor) -> None:
         visitor.visit_AggregationComparisonFilterWrapper(self)
+        comparison_filter = self.underlying_proto
+        if comparison_filter.HasField("formula"):
+            ColumnWrapper(comparison_filter.formula.left).accept(visitor)
+            ColumnWrapper(comparison_filter.formula.right).accept(visitor)
 
 
 class AggregationFilterWrapper(ProtoWrapper[AggregationFilter]):
diff --git a/tests/web/rpc/v1/test_conditional_aggregation.py b/tests/web/rpc/v1/test_conditional_aggregation.py
index 4ea54ff3cf..189b064046 100644
--- a/tests/web/rpc/v1/test_conditional_aggregation.py
+++ b/tests/web/rpc/v1/test_conditional_aggregation.py
@@ -14,12 +14,19 @@
     Column,
     TraceItemTableRequest,
 )
+from sentry_protos.snuba.v1.formula_pb2 import Literal
 from sentry_protos.snuba.v1.request_common_pb2 import RequestMeta, TraceItemType
 from sentry_protos.snuba.v1.trace_item_attribute_pb2 import (
     AttributeAggregation,
     AttributeKey,
+    AttributeValue,
     ExtrapolationMode,
     Function,
+    StrArray,
+)
+from sentry_protos.snuba.v1.trace_item_filter_pb2 import (
+    ComparisonFilter,
+    TraceItemFilter,
 )
 
 from snuba.web.rpc.proto_visitor import (
@@ -83,6 +90,63 @@ def _build_avg_conditional_aggregation_comparison_filter_with_name(
     )
 
 
+def _build_failure_rate_formula(deprecated: bool) -> Column.BinaryFormula:
+    """
+    Mirrors the `failure_rate()` formula clients send to EndpointTraceItemTable:
+    (count(status NOT IN [ok, cancelled, unknown]) * 1.0) / count(duration_ms).
+
+    The `right` count(duration_ms) leaf uses the deprecated `aggregation` field
+    when `deprecated` is True, and the newer `conditional_aggregation` otherwise.
+    Everything else is identical and must pass through the conversion unchanged.
+    """
+    duration_key = AttributeKey(type=AttributeKey.TYPE_DOUBLE, name="sentry.duration_ms")
+    if deprecated:
+        duration_count_column = Column(
+            aggregation=AttributeAggregation(
+                aggregate=Function.FUNCTION_COUNT,
+                key=duration_key,
+                extrapolation_mode=ExtrapolationMode.EXTRAPOLATION_MODE_SAMPLE_WEIGHTED,
+            )
+        )
+    else:
+        duration_count_column = Column(
+            conditional_aggregation=AttributeConditionalAggregation(
+                aggregate=Function.FUNCTION_COUNT,
+                key=duration_key,
+                extrapolation_mode=ExtrapolationMode.EXTRAPOLATION_MODE_SAMPLE_WEIGHTED,
+            )
+        )
+    return Column.BinaryFormula(
+        op=Column.BinaryFormula.OP_DIVIDE,
+        left=Column(
+            formula=Column.BinaryFormula(
+                op=Column.BinaryFormula.OP_MULTIPLY,
+                left=Column(
+                    conditional_aggregation=AttributeConditionalAggregation(
+                        aggregate=Function.FUNCTION_COUNT,
+                        key=AttributeKey(type=AttributeKey.TYPE_STRING, name="sentry.status"),
+                        extrapolation_mode=ExtrapolationMode.EXTRAPOLATION_MODE_SAMPLE_WEIGHTED,
+                        filter=TraceItemFilter(
+                            comparison_filter=ComparisonFilter(
+                                key=AttributeKey(
+                                    type=AttributeKey.TYPE_STRING, name="sentry.status"
+                                ),
+                                op=ComparisonFilter.OP_NOT_IN,
+                                value=AttributeValue(
+                                    val_str_array=StrArray(values=["ok", "cancelled", "unknown"])
+                                ),
+                            )
+                        ),
+                    )
+                ),
+                right=Column(literal=Literal(val_double=1.0)),
+                default_value_double=0.0,
+            )
+        ),
+        right=duration_count_column,
+    )
+
+
 _UNIMPORTANT_REQUEST_META = RequestMeta(
     project_ids=[1, 2, 3],
     organization_id=1,
@@ -326,6 +390,58 @@ def test_convert_aggregation_to_conditional_aggregation_in_having(self) -> None:
             )
         )
 
+    def test_convert_aggregation_to_conditional_aggregation_in_comparison_filter_formula(
+        self,
+    ) -> None:
+        # Mirrors the real failure_rate() query clients send: the same formula
+        # appears both as a SELECT column and inside the aggregation filter
+        # (the HAVING clause). Its count(duration_ms) leaf uses the deprecated
+        # `aggregation` field. The SELECT copy already converted via
+        # ColumnWrapper; the aggregation-filter copy did not, so the pipeline failed
+        message = TraceItemTableRequest(
+            meta=_UNIMPORTANT_REQUEST_META,
+            columns=[
+                Column(
+                    key=AttributeKey(type=AttributeKey.TYPE_STRING, name="sentry.transaction"),
+                    label="transaction",
+                ),
+                Column(
+                    formula=_build_failure_rate_formula(deprecated=True),
+                    label="failure_rate()",
+                ),
+            ],
+            aggregation_filter=AggregationFilter(
+                comparison_filter=AggregationComparisonFilter(
+                    formula=_build_failure_rate_formula(deprecated=True),
+                    op=AggregationComparisonFilter.OP_GREATER_THAN,
+                    val=0.5,
+                )
+            ),
+        )
+        aggregation_to_conditional_aggregation_visitor = (
+            AggregationToConditionalAggregationVisitor()
+        )
+        message_wrapper = TraceItemTableRequestWrapper(message)
+        message_wrapper.accept(aggregation_to_conditional_aggregation_visitor)
+
+        assert list(message.columns) == [
+            Column(
+                key=AttributeKey(type=AttributeKey.TYPE_STRING, name="sentry.transaction"),
+                label="transaction",
+            ),
+            Column(
+                formula=_build_failure_rate_formula(deprecated=False),
+                label="failure_rate()",
+            ),
+        ]
+        assert message.aggregation_filter == AggregationFilter(
+            comparison_filter=AggregationComparisonFilter(
+                formula=_build_failure_rate_formula(deprecated=False),
+                op=AggregationComparisonFilter.OP_GREATER_THAN,
+                val=0.5,
+            )
+        )
+
     def test_convert_aggregation_to_conditional_aggregation_in_all_of_select_and_order_by_and_having(
         self,
     ) -> None: