diff --git a/src/mudlib/combat/engine.py b/src/mudlib/combat/engine.py
index 18507df..c803d92 100644
--- a/src/mudlib/combat/engine.py
+++ b/src/mudlib/combat/engine.py
@@ -84,6 +84,8 @@ async def process_combat() -> None:
 
     This should be called each game loop tick to advance combat state machines.
     """
+    from mudlib.player import Player
+
     now = time.monotonic()
 
     for encounter in active_encounters[:]:  # Copy list to allow modification
@@ -92,8 +94,6 @@ async def process_combat() -> None:
             await encounter.attacker.send("Combat has fizzled out.\r\n")
             await encounter.defender.send("Combat has fizzled out.\r\n")
 
-            from mudlib.player import Player
-
             for entity in (encounter.attacker, encounter.defender):
                 if isinstance(entity, Player) and entity.mode == "combat":
                     entity.mode_stack.pop()
@@ -149,8 +149,6 @@ async def process_combat() -> None:
                 await viewer.send(msg + "\r\n")
 
             # Send vitals update after damage resolution
-            from mudlib.player import Player
-
             for entity in (encounter.attacker, encounter.defender):
                 if isinstance(entity, Player):
                     send_char_vitals(entity)
@@ -168,6 +166,17 @@ async def process_combat() -> None:
                     loser = encounter.attacker
                     winner = encounter.defender
 
+                # Track kill/death stats
+                if isinstance(winner, Player):
+                    winner.kills += 1
+                    if isinstance(loser, Mob):
+                        winner.mob_kills[loser.name] = (
+                            winner.mob_kills.get(loser.name, 0) + 1
+                        )
+
+                if isinstance(loser, Player):
+                    loser.deaths += 1
+
                 # Despawn mob losers, send victory/defeat messages
                 if isinstance(loser, Mob):
                     from mudlib.corpse import create_corpse
@@ -191,8 +200,6 @@ async def process_combat() -> None:
                     )
 
                 # Pop combat mode from both entities if they're Players
-                from mudlib.player import Player
-
                 attacker = encounter.attacker
                 if isinstance(attacker, Player) and attacker.mode == "combat":
                     attacker.mode_stack.pop()
diff --git a/src/mudlib/player.py b/src/mudlib/player.py
index f153a31..7eb219f 100644
--- a/src/mudlib/player.py
+++ b/src/mudlib/player.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import asyncio
+import time
 from dataclasses import dataclass, field
 from typing import TYPE_CHECKING, Any
 
@@ -90,5 +91,16 @@ class Player(Entity):
         )
 
 
+def accumulate_play_time(player: Player) -> None:
+    """Accumulate play time since session start and reset timer.
+
+    Args:
+        player: The player to update
+    """
+    if player.session_start > 0:
+        player.play_time_seconds += time.monotonic() - player.session_start
+        player.session_start = time.monotonic()
+
+
 # Global registry of connected players
 players: dict[str, Player] = {}
diff --git a/src/mudlib/store/__init__.py b/src/mudlib/store/__init__.py
index 8b8e801..38bf051 100644
--- a/src/mudlib/store/__init__.py
+++ b/src/mudlib/store/__init__.py
@@ -226,6 +226,11 @@ def save_player(player: Player) -> None:
     Args:
         player: Player instance to save
     """
+    # Accumulate play time before saving
+    from mudlib.player import accumulate_play_time
+
+    accumulate_play_time(player)
+
     # Serialize inventory as JSON list of thing names
     inventory_names = [obj.name for obj in player.contents if isinstance(obj, Thing)]
     inventory_json = json.dumps(inventory_names)
diff --git a/tests/test_kill_tracking.py b/tests/test_kill_tracking.py
new file mode 100644
index 0000000..ca53f82
--- /dev/null
+++ b/tests/test_kill_tracking.py
@@ -0,0 +1,154 @@
+"""Tests for kill and death tracking in combat."""
+
+import time
+
+import pytest
+
+from mudlib.combat.engine import (
+    process_combat,
+    start_encounter,
+)
+from mudlib.combat.moves import CombatMove
+from mudlib.entity import Mob
+from mudlib.player import accumulate_play_time
+
+
+@pytest.fixture
+def punch_move():
+    """Create a basic punch move for testing."""
+    return CombatMove(
+        name="punch right",
+        move_type="attack",
+        stamina_cost=5.0,
+        timing_window_ms=800,
+        damage_pct=0.15,
+        countered_by=[],
+        resolve_hit="{attacker} hits {defender}!",
+        resolve_miss="{defender} dodges!",
+        announce="{attacker} punches!",
+    )
+
+
+@pytest.mark.asyncio
+async def test_player_kills_mob_increments_stats(player, test_zone, punch_move):
+    """Player kills mob -> kills incremented, mob_kills tracked."""
+    # Create a goblin mob
+    goblin = Mob(name="goblin", x=0, y=0)
+    goblin.location = test_zone
+    test_zone._contents.append(goblin)
+
+    # Start encounter
+    encounter = start_encounter(player, goblin)
+
+    # Execute attack
+    encounter.attack(punch_move)
+
+    # Advance past telegraph (0.3s) + window (0.8s)
+    encounter.tick(time.monotonic() + 0.31)  # -> WINDOW
+    encounter.tick(time.monotonic() + 1.2)  # -> RESOLVE
+
+    # Set defender to very low pl so damage kills them
+    goblin.pl = 1.0
+
+    # Process combat (this will resolve and end encounter)
+    await process_combat()
+
+    # Verify stats
+    assert player.kills == 1
+    assert player.mob_kills["goblin"] == 1
+
+
+@pytest.mark.asyncio
+async def test_player_killed_by_mob_increments_deaths(player, test_zone, punch_move):
+    """Player killed by mob -> deaths incremented."""
+    # Create a goblin mob
+    goblin = Mob(name="goblin", x=0, y=0)
+    goblin.location = test_zone
+    test_zone._contents.append(goblin)
+
+    # Start encounter with mob as attacker
+    encounter = start_encounter(goblin, player)
+
+    # Execute attack
+    encounter.attack(punch_move)
+
+    # Advance to RESOLVE
+    encounter.tick(time.monotonic() + 0.31)
+    encounter.tick(time.monotonic() + 1.2)
+
+    # Set player to low pl so they die
+    player.pl = 1.0
+
+    # Process combat
+    await process_combat()
+
+    # Verify deaths incremented
+    assert player.deaths == 1
+
+
+@pytest.mark.asyncio
+async def test_multiple_kills_accumulate(player, test_zone, punch_move):
+    """After killing 3 goblins, player.kills == 3, player.mob_kills["goblin"] == 3."""
+    for _ in range(3):
+        # Create goblin
+        goblin = Mob(name="goblin", x=0, y=0)
+        goblin.location = test_zone
+        test_zone._contents.append(goblin)
+
+        # Create and resolve encounter
+        encounter = start_encounter(player, goblin)
+        encounter.attack(punch_move)
+        encounter.tick(time.monotonic() + 0.31)
+        encounter.tick(time.monotonic() + 1.2)
+        goblin.pl = 1.0
+
+        await process_combat()
+
+    # Verify accumulated kills
+    assert player.kills == 3
+    assert player.mob_kills["goblin"] == 3
+
+
+def test_session_time_tracking(player):
+    """Session time tracking accumulates correctly."""
+    # Set session start to a known time
+    start_time = time.monotonic()
+    player.session_start = start_time
+
+    # Simulate 5 seconds passing
+    time.sleep(0.01)  # Small real delay to ensure monotonic() advances
+    player.session_start = start_time  # Reset for predictable test
+
+    # Mock time to be 5 seconds later
+    import unittest.mock
+
+    with unittest.mock.patch("time.monotonic", return_value=start_time + 5.0):
+        accumulate_play_time(player)
+
+    # Should have accumulated 5 seconds
+    assert player.play_time_seconds == 5.0
+
+    # Session start should be reset to current time
+    with unittest.mock.patch("time.monotonic", return_value=start_time + 5.0):
+        assert player.session_start == start_time + 5.0
+
+
+def test_accumulate_play_time_multiple_sessions(player):
+    """Multiple accumulation calls should add up correctly."""
+    start_time = time.monotonic()
+    player.session_start = start_time
+
+    import unittest.mock
+
+    # First accumulation: 3 seconds
+    with unittest.mock.patch("time.monotonic", return_value=start_time + 3.0):
+        accumulate_play_time(player)
+
+    assert player.play_time_seconds == 3.0
+
+    # Second accumulation: 2 more seconds (from reset point)
+    with unittest.mock.patch("time.monotonic", return_value=start_time + 5.0):
+        accumulate_play_time(player)
+
+    # Should have 3 + 2 = 5 total
+    assert player.play_time_seconds == 5.0