diff --git a/pyiceberg/table/__init__.py b/pyiceberg/table/__init__.py
index 7f1524642b..87eddcc01f 100644
--- a/pyiceberg/table/__init__.py
+++ b/pyiceberg/table/__init__.py
@@ -861,6 +861,28 @@ def upsert(
 
         return UpsertResult(rows_updated=update_row_cnt, rows_inserted=insert_row_cnt)
 
+    def _find_referenced_data_files(self, file_paths: list[str]) -> list[str]:
+        """Return file_paths already referenced by data files in the current snapshot."""
+        snapshot = self.table_metadata.current_snapshot()
+        if snapshot is None:
+            return []
+
+        candidates = set(file_paths)
+        io = self._table.io
+        data_manifests = [m for m in snapshot.manifests(io) if m.content == ManifestContent.DATA]
+
+        def path_filter(data_file: DataFile) -> bool:
+            return data_file.file_path in candidates
+
+        executor = ExecutorFactory.get_or_create()
+        entries = chain.from_iterable(
+            executor.map(
+                lambda args: _open_manifest(*args),
+                [(io, manifest, path_filter, lambda _: True) for manifest in data_manifests],
+            )
+        )
+        return [entry.data_file.file_path for entry in entries]
+
     def add_files(
         self,
         file_paths: list[str],
@@ -883,11 +905,7 @@ def add_files(
             raise ValueError("File paths must be unique")
 
         if check_duplicate_files:
-            import pyarrow.compute as pc
-
-            expr = pc.field("file_path").isin(file_paths)
-            referenced_files = [file["file_path"] for file in self._table.inspect.data_files().filter(expr).to_pylist()]
-
+            referenced_files = self._find_referenced_data_files(file_paths)
             if referenced_files:
                 raise ValueError(f"Cannot add files that are already referenced by table, files: {', '.join(referenced_files)}")
 
diff --git a/tests/benchmark/test_add_files_dup_check_benchmark.py b/tests/benchmark/test_add_files_dup_check_benchmark.py
new file mode 100644
index 0000000000..731305bf02
--- /dev/null
+++ b/tests/benchmark/test_add_files_dup_check_benchmark.py
@@ -0,0 +1,132 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+"""Memory benchmark for `add_files(check_duplicate_files=True)`.
+
+Reproduces the per-call cost of the duplicate-files check on a growing
+table. Before fix: each call materializes every DataFile in the snapshot
+into a pyarrow Table (with readable_metrics, partition decode, full stats
+dicts) and post-filters on file_path — peak memory grows roughly linearly
+with cumulative file count, dominated by per-column stats decoding.
+After fix: streaming manifest scan with set containment on file_path,
+peak memory stays flat.
+
+Run with: uv run pytest tests/benchmark/test_add_files_dup_check_benchmark.py -v -s -m benchmark
+"""
+
+from __future__ import annotations
+
+import gc
+import tempfile
+import tracemalloc
+from pathlib import Path
+from typing import Any
+
+import pyarrow as pa
+import pyarrow.parquet as pq
+import pytest
+
+from pyiceberg.catalog.memory import InMemoryCatalog
+from pyiceberg.schema import Schema
+from pyiceberg.types import IntegerType, NestedField, StringType
+
+
+@pytest.fixture
+def memory_catalog(tmp_path_factory: pytest.TempPathFactory) -> InMemoryCatalog:
+    warehouse_path = str(tmp_path_factory.mktemp("warehouse"))
+    catalog = InMemoryCatalog("memory_test", warehouse=f"file://{warehouse_path}")
+    catalog.create_namespace("default")
+    return catalog
+
+
+def _wide_schema(num_columns: int = 30) -> tuple[Schema, pa.Schema]:
+    """Build a wide-ish schema so per-column stats decoding has work to do."""
+    iceberg_fields = [NestedField(field_id=1, name="id", field_type=IntegerType(), required=True)]
+    for i in range(2, num_columns + 1):
+        iceberg_fields.append(NestedField(field_id=i, name=f"col_{i}", field_type=StringType(), required=False))
+    iceberg_schema = Schema(*iceberg_fields)
+    arrow_schema = pa.schema(
+        [pa.field("id", pa.int32(), nullable=False)]
+        + [pa.field(f"col_{i}", pa.string(), nullable=True) for i in range(2, num_columns + 1)]
+    )
+    return iceberg_schema, arrow_schema
+
+
+def _write_files(work_dir: Path, batch_idx: int, n_files: int, arrow_schema: pa.Schema) -> list[str]:
+    paths: list[str] = []
+    columns: dict[str, list[Any]] = {
+        name: list(range(8)) if name == "id" else [f"v{batch_idx}-{j}" for j in range(8)] for name in arrow_schema.names
+    }
+    rows = pa.Table.from_pydict(columns, schema=arrow_schema)
+    for i in range(n_files):
+        p = work_dir / f"batch_{batch_idx:03d}_file_{i:05d}.parquet"
+        pq.write_table(rows, p)
+        paths.append(f"file://{p}")
+    return paths
+
+
+@pytest.mark.benchmark
+def test_add_files_dup_check_memory_growth(memory_catalog: InMemoryCatalog) -> None:
+    """Peak memory per `add_files(check_duplicate_files=True)` call should stay
+    flat across consecutive calls on a growing table.
+
+    With the materialize-then-filter implementation, peak grows roughly linearly
+    with cumulative file count (per-column stats decoding into a pyarrow Table).
+    With the streaming-scan implementation, peak stays bounded by the per-call
+    workload.
+    """
+    num_batches = 10
+    files_per_batch = 200
+    iceberg_schema, arrow_schema = _wide_schema(num_columns=30)
+
+    with tempfile.TemporaryDirectory() as tmp_root:
+        data_dir = Path(tmp_root) / "data"
+        data_dir.mkdir()
+        table = memory_catalog.create_table("default.add_files_bench", schema=iceberg_schema)
+
+        gc.collect()
+        tracemalloc.start()
+
+        peaks_mb: list[float] = []
+        print(f"\n--- add_files dup-check benchmark ({num_batches} batches × {files_per_batch} files, 30 cols) ---")
+        print(f"{'batch':>5} {'tracemalloc_peak_MB':>22} {'cumulative_files':>17}")
+
+        cumulative = 0
+        for b in range(num_batches):
+            paths = _write_files(data_dir, b, files_per_batch, arrow_schema)
+            tracemalloc.reset_peak()
+            table.add_files(file_paths=paths, check_duplicate_files=True)
+            _, peak = tracemalloc.get_traced_memory()
+            peak_mb = peak / (1024 * 1024)
+            peaks_mb.append(peak_mb)
+            cumulative += files_per_batch
+            print(f"{b:>5d} {peak_mb:>22.1f} {cumulative:>17d}")
+
+        tracemalloc.stop()
+
+        # Growth ratio: last call peak vs first call peak.
+        # Materialize-then-filter (pre-fix): observed ~7× on this workload.
+        # Streaming scan (post-fix): observed ~1×–1.5× (mostly noise).
+        # Threshold of 3× catches the regression while tolerating variance.
+        first_peak = peaks_mb[0]
+        last_peak = peaks_mb[-1]
+        ratio = last_peak / first_peak if first_peak > 0 else float("inf")
+        print(f"\n  Peak ratio (last / first): {ratio:.1f}×")
+        max_ratio = 3.0
+        assert ratio < max_ratio, (
+            f"Peak memory ratio ({ratio:.1f}×) exceeds {max_ratio}×. "
+            "Dup-check materializes the full snapshot rather than streaming on file_path."
+        )