Sneak Attacks

[TheMeanDM]

Can they stack with Eldritch Blast?

Sneak Attack
If a rogue can catch an opponent when he is unable to defend himself effectively from her attack, she can strike a vital spot for extra damage.

The rogue’s attack deals extra damage any time her target would be denied a Dexterity bonus to AC (whether the target actually has a Dexterity bonus or not), or when the rogue flanks her target. This extra damage is 1d6 at 1st level, and it increases by 1d6 every two rogue levels thereafter. Should the rogue score a critical hit with a sneak attack, this extra damage is not multiplied.

Ranged attacks can count as sneak attacks only if the target is within 30 feet.

With a sap (blackjack) or an unarmed strike, a rogue can make a sneak attack that deals nonlethal damage instead of lethal damage. She cannot use a weapon that deals lethal damage to deal nonlethal damage in a sneak attack, not even with the usual -4 penalty.

A rogue can sneak attack only living creatures with discernible anatomies—undead, constructs, oozes, plants, and incorporeal creatures lack vital areas to attack. Any creature that is immune to critical hits is not vulnerable to sneak attacks. The rogue must be able to see the target well enough to pick out a vital spot and must be able to reach such a spot. A rogue cannot sneak attack while striking a creature with concealment or striking the limbs of a creature whose vitals are beyond reach.

Eldritch Blast
The First ability a warlock learns is eldritch blast. A warlock attacks his foes with eldritch power, using baleful magical energy to deal damage and sometimes impart other debilitating effects.

An eldritch blast is a ray with a range of 60 feet. It is a ranged touch attack that affects a single target, allowing no saving throw.

[AslanCross]

Sure he can. Anything that requires an attack roll can qualify for Sneak Attack.

[Cowboy_ninja]

dito to that. Look in the Complete arcane for "Weapon-like-spells" it will answer most questions on this topic.

[kamikasei]

The reference text for this is in Complete Arcane, I believe (AFB at the moment). Look for a sidebar or paragraph on "weaponlike spells". This clarifies what spells can benefit from Sneak Attack, and Eldritch Blast counts.

edit: not just ninja'd but cowboy'd to boot...

[Person_Man]

Yes. However, its not a particularly good combo. Sneak Attacks and Eldritch Blast scale at the same exact rate (+1d6 every other level, an average of +1.75 damage per level).

If you want to maximize Sneak Attack damage, you need to maximize your # of attacks per round. If you want touch attacks, buy a Wand of Flame Blade and use UMD, or take a one level dip into Pyrokineticist, or be a Rogue-caster build and use Wraithstrike or Spectral Weapon.

If you want to improve your Eldritch Blast, just look into some of the great Warlock PrC and Invocations in the various splat books out there. They can add some really excellent effects, though only a few of them add a ton of RAW damage.

[Overlard]

What is useful is 1 level of warlock for your rogue though. Besides a useful invocation, you get an at-will ranged-touch attack, that qualifies for sneak attack & bypasses damage reduction entirely. If you're only able to get off a single attack, or your opponent's AC is too high for a decent chance of success from a normal attack, then it's an excellent way to do a handful of d6 damage to him. SR is a problem of course, but you can't have everything.

[Chronos]

Sure he can. Anything that requires an attack roll can qualify for Sneak Attack.

Addendum: Anything that requires an attack roll and deals damage. Which still works with Eldritch Blast, but you can't Sneak Attack with, say, a Ray of Exhaustion.

Attacks which do ability score damage add negative energy HP damage for the Sneak Attack. Otherwise, the Sneak Attack damage is of the same sort as the original attack (so a high-level rogue with a Ray of Frost will do 1d3 plus a bunch of d6 of cold damage, for instance).