Free 2-Day Shipping on Orders Over $50

Detail Images

  • Osprey Packs - Mutant 38L Backpack -

Current Color

  • Osprey Packs - Mutant 38L Backpack -

Osprey Packs Mutant 38L Backpack

Temporarily Out Of Stock

Don't get too bummed. This item is on the way and will be available for purchase as soon as it rolls into the warehouse.

Can't wait? Consider one of the other Men's Technical Daypacks we have in stock.

View Similar Products

6 Reviews


Climb like a mutant.

High on a ridgeline, winds swirling around your perch, the stability of your pack and gear is of paramount importance—that's why a pack like the Osprey Mutant 38 Backpack is so important. Support and stability come in the form of a removable HDPE framesheet, a removable aluminum stay, and an AirScape back panel that also ventilates as you climb. This top-loading pack features a removable floating top lid to lighten your load for summit day. When removed, you can protect and secure your gear with the FlapJacket closure system. 

To help you haul everything you need, Osprey added its Mutant Dual ToolLock ice-tool system that lets you securely carry, and remove, tools when needed. Side compression straps let you secure your load if it's not quite full, and the A-frame ski carry makes sure that you can get down off the top the fun way. To help keep you from overheating on the way up you can store your helmet in the removable helmet-carry system up top.

  • Reverse wrap hybrid EVA foam hip belt
  • Removable 1.2mm HDPE framesheet
  • Removable aluminum stay
  • AirScape back panel
  • 35-50lb optimum load range
  • Top-load access
  • Removable floating top lid
  • Nylon and polyester
  • FlapJacket closure
  • Internal hydration sleeve fits up to 3L bladder (reservoir not included)
  • Zippered top pocket
  • Zippered mesh pocket under FlapJacket
  • Mutant Dual ToolLock ice-tool system
  • Integrated gear loops on hip belt
  • Side compression straps
  • A-frame ski carry
  • Removable helmet carry system
  • Item #OSP003D

Tech Specs

nylon & polyester
[small/medium] 35L (2136cu in), [medium/large] 38L (2319cu in)
removable 1.2mm HDPE framesheet, removable aluminum stay, AirScape back panel
Waist Belt
yes, Reverse wrap hybrid EVA foam hip belt
Hydration Compatible
yes, internal sleeve, up to 3-liter
Reservoir Included
1 zippered top pocket, 1 zippered mesh pocket
Gear Loops
yes, hip belt
Helmet Carry
yes, removable stretch mesh
Ice Axe Carry
yes, Mutant Dual ToolLock system
yes, removable side
Rain Cover
yes, FlapJacket
Weight Capacity
35 - 50 lbs
[M/L] 25 x 11 x 10 in
Claimed Weight
[S/M] 2 lbs 7 oz, [M/L] 2 lbs 10 oz
Recommended Use
alpine & expedition, mountaineering
Manufacturer Warranty

Tech Specs

  • Reviews
  • Q & A

What do you think about this product?

Have questions about this product?

Day Pack turned Ski Pack

  • Familiarity: I've put it through the wringer

I originally picked this pack up a year ago, because I wanted it to be my 14er day pack for when I was living in Colorado. It was the perfect size, I could fit all my layers plus 3 liters of water and was not an awkward pack fit. I had spent months obsessing over what the perfect pack would be.

This winter- I was in pack debate mode again and this time for a ski touring pack. And while I was looking at a variety of packs with ski specific pockets and designs I panicked and it was mere days before my trip.

So I took the mutant because the side straps could also carry my skis with ease! And off I went to ski tour in Yellowstone National Park! And it was great- I figured out the perfect organization system and because I always run thirsty I still put my 3 liter bladder in everyday as well. It worked out way better than I expected and I really love this pack!

I bought it because I knew how versatile it was but it truly has turned out to do a little bit of everything quite well. And It's an Osprey- which means it has a life time guarantee and is built super burly! I love high quality packs- they really make all the difference!

Osprey's Hermione Granger Bag

  • Familiarity: I've used it once or twice and have initial impressions

People don't think about it much, but packs really are about balance. Making sure a pack is equally weighted is incredibly important for strapping things to it; having too much weight on any side, and you are going to have an unhappy back. This Osprey Mutant 38 seems to understand this incredibly well, by adding tons of places to strap stuff to your the pack.

Background on me: I am a backcountry skiier, and I am not really into mountaineering too much. However, for this pack, I decided to do a little test and add my typically ski stuff, as well as some typical ski mountaineering gear. How did it fare? In a word: phenomenally. In the picture posted, everything I have in that pack is:

-a beacon, shovel, and probe

-2 sets of gloves (hardshell and softshell)

-3 different jackets (hardshell, light touring jacket, and puffy jacket)

-2 sets of goggles

-touring skins

-snacks and water

As well as a pair of skis, ice axes, and my helmet on the outside of the pack. All of this, and I still feel like I had room for a smaller repelling rope, harness, and belay device if I needed. At zero point did I ever say "man, this thing is small. In fact, the opposite happened: "Did Hermione Granger make this bag, cause apparently this thing never ends." The best part is that at no point did I ever feel like I was going to be tipping over, or that the pack was angled weird. It sat perfectly dead center on my back, and was super easy to carry.


-Uber light. Like, jokes at a funeral light.

-Spacious. I think I could fit a SmartCar in this bag.

-Well balanced. Walking tight ropes with this pack on will be a breeze.

-The flap over the opening of the the bag. I would have never thought of it myself, but it actually reaaaly helps with keep snow and moisture out of your bag.


The helmet carry. Whoever designed the inside of the bag obviously didn't give any tips to the person making the helmet carry. First of all, its on top of the bag. This makes the pack a little top heavy when carrying lighter loads. Also, this thing is reeeeaaaly bad at carrying bigger helmets. I have an XL Smith Gage, and it doesn't seem to be able to cover the entire helmet. In fact, it actually slipped out of the carry while on the trail, which was incredibly annoying.

-I wish it had a avalanche safety pocket. I do realize this is not specifically geared toward ski touring, but it definitely would have nice to see.

-The padding on the hip belt. Does it work? Yes. Can I see it being reeealy uncomfortable at long distance? Also yes.

Overall, really like this pack. Like a lot. I may even like like it. Other than a couple minor things, I would seriously recommend this pack to anyone doing backcountry skiing, ski mountaineering, and even general climbing.

Osprey's Hermione Granger Bag

Great lightweight pack

  • Familiarity: I've used it several times

I bought this as a spring ski mountaineering pack, but spring was over so I didn't try it for that yet. Just tried it for hiking so far. It is super light. There are a few things I wonder about. There is almost no padding on the waist belt and the water hose just comes out from a hole. That should be fine in the spring but if I tried to use this in the winter the hose might freeze. I really need to load it up with full gear including skis, crampons, ice axe, to see how it carries. I know they had to cut some features to lighten it up. I like the high usable to unusable feature ratio. I also have a Kode 42 and that pack could lose a bunch of features I don't need (board carrying straps, back side full zipper, etc) and get a lot lighter and still be just as functional for me. The Mutant has most features I need (ski carry, helmet sling, hole for water bladder etc) without a bunch of stuff I don't need. I am giving it a 4 because if it had waist belt padding I think it would be just about perfect.

Fantastic do-it-all pack

  • Familiarity: I've used it several times

I have carried mine on a 3 week trip through Europe, and backpacking trips in the Sierras. It's been great for both things.
I really like the flap that goes over when one removes the top pocket. I've carried up to 30#, and it handles it well. It appears to be durable, though I haven't done any hauling with it yet... Overall I'm very impressed.

It's an Osprey...

  • Familiarity: I've put it through the wringer

I have become a cheerleader for Osprey and I'm slightly impartial. Their packs are always feature rich, comfortable, and protected by the best warranty in the business. I own three packs from Osprey (including this one) and I've had to use the warranty twice. It is true what they say; it will get fixed for free (even if your dog chews on it like mine).

I bought this pack for multi-pitch and alpine climbing for its removable frame, compression straps, and features (like the awesome helmet holder). I love it so much that it is now my day-pack for hiking and may even get used for ultralight overnight trips. Highly recommended!

What size will fit an 18" torso? It looks like the size chart is slightly out of date for this model. The newer versions is only offered in two sizes instead of three.


The S/M is the size you'll want for an 18" torso.

S/M is 15-19"

L/XL is 19-22"

Hope this helps!

Shoot me an email anytime you have questions!

Jared D.

Expert Gearhead