Defense is both a unit attribute and a gameplay mechanic in XCOM: Enemy Unknown.


Defense directly decreases an enemy's chance to hit the unit with most weapons. It does not reduce the damage sustained when hit. Note that melee attacks, area of effect weapons (such as grenades and rocket launchers), and offensive abilities ignore a unit's Defense attribute and always hit.

Chance to HitEdit

A unit's chance to hit is:

Shooter's Aim - Target's Defense ± Weapon Range Modifier

The game mechanic adds the shooter's Aim attribute to any applicable Aim modifiers (abilities, items, etc.), subtracts the target's Defense attribute and modifiers, then adds or subtracts a weapon range modifier (if applicable), to determine the chance to hit.

For example, an enemy with 65 Aim has a 65% chance to hit (without taking into account weapon range and other modifiers). A soldier in full cover is granted 40 Defense, giving the shot a 25% chance to hit.

When aiming a shot, the player can select "More Info" to see a list of modifiers that are currently being applied.




Aliens have an innate Defense attribute that is determined by their species and the game difficulty:

Alien Defense
Species Defense Species Defense
Berserker20 · 20 · 20 · 20 Muton Elite20 · 20 · 30 · 30
Chryssalid10 · 10 · 10 · 10 Outsider0 · 0 · 10 · 10
Cyberdisc10 · 10 · 10 · 10 Sectoid0 · 0 · 0 · 0
Drone10 · 10 · 10 · 10   Sectoid Commander  20 · 20 · 20 · 20
Ethereal40 · 40 · 40 · 40 Sectopod30 · 30 · 30 · 30
Floater0 · 0 · 0 · 0 Seeker EW10 · 10 · 20 · 20
Heavy Floater10 · 10 · 10 · 10 Thin Man0 · 0 · 0 · 0
Mechtoid EW10 · 10 · 10 · 10 Uber Ethereal40 · 40 · 40 · 50
Muton10 · 10 · 10 · 10 Zombie0 · 0 · 0 · 0
Easy · Normal · Classic · ImpossibleSource: DefaultGameCore.ini, XCOM: Enemy Within


All EXALT members have an innate Defense attribute of 0.


Main article: Cover

Using cover increases a unit's Defense. Conversely, units receive a +50% critical chance bonus when targeting an exposed enemy. These factors combine to make cover the most frequently used method of boosting a unit's Defense. There are two types of cover available, full and partial:

Full cover: +40 Defense
Partial cover: +20 Defense

All EXALT units and most alien species can use cover for Defense bonuses equal to XCOM's. Chryssalids, Cyberdiscs, Drones, Ethereals, MEC Troopers, Mechtoids, Sectopods, Uber Ethereals, Zombies, and all varieties of S.H.I.V.s cannot use cover.

Bonuses and PerksEdit

Beyond the use of cover, there are a substantial number of ways to increase a unit's Defense.

Basic Abilities and TraitsEdit

Ability / Trait Description
XEU AlienAbility Evasion  Evasion +20 Defense when airborne.
XCOM: Soldiers equipped with Archangel Armor
Enemies: Cyberdisc, Drone, Floater, Heavy Floater, Seeker
XComEU Head Down icon  Head Down +10 Defense, even when not in cover.
XCOM: Civilians only
Enemies: None
XEU Hunker Down icon  Hunker Down  Doubles the cover Defense bonus.
XCOM: Assault, Heavy, Sniper, Support
Enemies: All Muton species, All EXALT units

Class AbilitiesEdit

Class Ability Description
XEU ClassAssault
XEU Assault TacticalSense  Tactical Sense +5 Defense per enemy in sight (max +20).
XComEW MEC Trooper logo trans
Automated Threat Assessment Icon  Automated Threat Assessment Confers +15 Defense when in Overwatch.
Distortion Field Icon  Distortion Field Nearby allies in cover receive +10 Defense. (Support-based MEC Troopers)
XComEU Psionic icon
XEU Psionic TelekineticField  Telekinetic Field Grants +40 Defense to all units within the field.
XEU ClassSniper
XEU Sniper DamnGoodGround  Damn Good Ground Confers +10 Aim and +10 Defense against enemies at a lower elevation.
XEU Sniper LowProfile  Low Profile Makes partial cover count as full.
XEU ClassSupport
XEU Support DenseSmoke  Dense Smoke Smoke Grenades increase Defense by +40 instead of +20.
XEU Support SmokeGrenade  Smoke Grenade Confers +20 Defense to all units in the smoke cloud.

Body ArmorEdit

Armor Description
XComEU Ghost Armor transbg  Ghost Armor Confers +20 Defense. 
XComEU Psi Armor transbg  Psi Armor Confers +10 Defense.
XComEU Skeleton Suit transbg  Skeleton Suit   Confers +10 Defense.

MEC SuitsEdit

MEC Suit Description
XComEW MEC-1 Warden transbg  MEC-1 Warden EW Confers +10 Defense. 
XComEW MEC-2 Sentinel transbg  MEC-2 Sentinel EW   Confers +10 Defense.
XComEW MEC-3 Paladin transbg  MEC-3 Paladin EW Confers +10 Defense.


Medal Description
XComEW Medals - Star of Terra icon 1 will  Star of Terra EW Entire squad receives +5 Will and +5 Defense in battle.
XComEW Medals - Urban Combat Badge icon 1 defense  Urban Combat Badge EW  +5 Defense when in cover.
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