diff --git a/backend/app/api/portfolio.py b/backend/app/api/portfolio.py
index ffacb40..d4fa1d5 100644
--- a/backend/app/api/portfolio.py
+++ b/backend/app/api/portfolio.py
@@ -373,7 +373,7 @@ async def apply_rebalance(
     db: Session = Depends(get_db),
 ):
     """리밸런싱 결과를 적용하여 거래를 일괄 생성한다."""
-    from datetime import datetime
+    from datetime import datetime, timezone
 
     portfolio = _get_portfolio(db, portfolio_id, current_user.id)
     transactions = []
@@ -387,7 +387,7 @@ async def apply_rebalance(
             tx_type=tx_type,
             quantity=item.quantity,
             price=item.price,
-            executed_at=datetime.utcnow(),
+            executed_at=datetime.now(timezone.utc),
             memo="리밸런싱 적용",
         )
         db.add(transaction)
diff --git a/backend/app/api/signal.py b/backend/app/api/signal.py
index 8ad625d..c718560 100644
--- a/backend/app/api/signal.py
+++ b/backend/app/api/signal.py
@@ -1,7 +1,7 @@
 """
 KJB Signal API endpoints.
 """
-from datetime import date, datetime
+from datetime import date, datetime, timezone
 from typing import List, Optional
 
 from fastapi import APIRouter, Depends, HTTPException, Query
@@ -91,7 +91,7 @@ async def execute_signal(
         tx_type=tx_type,
         quantity=data.quantity,
         price=data.price,
-        executed_at=datetime.utcnow(),
+        executed_at=datetime.now(timezone.utc),
         memo=f"KJB signal #{signal.id}: {signal.signal_type.value}",
     )
     db.add(transaction)
@@ -130,7 +130,7 @@ async def execute_signal(
     signal.status = SignalStatus.EXECUTED
     signal.executed_price = data.price
     signal.executed_quantity = data.quantity
-    signal.executed_at = datetime.utcnow()
+    signal.executed_at = datetime.now(timezone.utc)
 
     db.commit()
     db.refresh(transaction)
diff --git a/backend/app/services/backtest/worker.py b/backend/app/services/backtest/worker.py
index bdca866..da965a9 100644
--- a/backend/app/services/backtest/worker.py
+++ b/backend/app/services/backtest/worker.py
@@ -1,7 +1,7 @@
 """
 Background worker for backtest execution.
 """
-from datetime import datetime
+from datetime import datetime, timezone
 from concurrent.futures import ThreadPoolExecutor
 import logging
 
@@ -35,7 +35,7 @@ def _run_backtest_job(backtest_id: int) -> None:
 
     try:
         # Update status to running
-        backtest = db.query(Backtest).get(backtest_id)
+        backtest = db.get(Backtest, backtest_id)
         if not backtest:
             logger.error(f"Backtest {backtest_id} not found")
             return
@@ -54,7 +54,7 @@ def _run_backtest_job(backtest_id: int) -> None:
 
         # Update status to completed
         backtest.status = BacktestStatus.COMPLETED
-        backtest.completed_at = datetime.utcnow()
+        backtest.completed_at = datetime.now(timezone.utc)
         db.commit()
         logger.info(f"Backtest {backtest_id} completed successfully")
 
@@ -63,11 +63,11 @@ def _run_backtest_job(backtest_id: int) -> None:
 
         # Update status to failed
         try:
-            backtest = db.query(Backtest).get(backtest_id)
+            backtest = db.get(Backtest, backtest_id)
             if backtest:
                 backtest.status = BacktestStatus.FAILED
                 backtest.error_message = str(e)[:1000]  # Limit error message length
-                backtest.completed_at = datetime.utcnow()
+                backtest.completed_at = datetime.now(timezone.utc)
                 db.commit()
         except Exception as commit_error:
             logger.exception(f"Failed to update backtest status: {commit_error}")
diff --git a/backend/app/services/collectors/base.py b/backend/app/services/collectors/base.py
index 5b803a7..d5414f1 100644
--- a/backend/app/services/collectors/base.py
+++ b/backend/app/services/collectors/base.py
@@ -4,7 +4,7 @@ Base collector class for data collection jobs.
 import logging
 import re
 from abc import ABC, abstractmethod
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Optional
 
 import requests
@@ -44,7 +44,7 @@ class BaseCollector(ABC):
         self.job_log = JobLog(
             job_name=self.job_name,
             status="running",
-            started_at=datetime.utcnow(),
+            started_at=datetime.now(timezone.utc),
         )
         self.db.add(self.job_log)
         self.db.commit()
@@ -55,7 +55,7 @@ class BaseCollector(ABC):
         if self.job_log:
             try:
                 self.job_log.status = "success"
-                self.job_log.finished_at = datetime.utcnow()
+                self.job_log.finished_at = datetime.now(timezone.utc)
                 self.job_log.records_count = records_count
                 self.db.commit()
             except Exception:
@@ -67,7 +67,7 @@ class BaseCollector(ABC):
         if self.job_log:
             try:
                 self.job_log.status = "failed"
-                self.job_log.finished_at = datetime.utcnow()
+                self.job_log.finished_at = datetime.now(timezone.utc)
                 self.job_log.error_msg = error_msg
                 self.db.commit()
             except Exception: