Is this bag machine washable?

Yes, it is machine washable, and is easy to wash. It does take time, though. From Mountain Hardware's Care Instructions Machine Wash: Zip up all the zippers, attach all Velcro and turn the bag inside out. Wash in a front-loading machine with cold water on the gentle or delicate setting. We recommend that you use the minimum amount of cleaning agent [I never use more than 1/4 cup - less is more] and scrub the head and foot section before you wash the entire bag. Use at least two rinse cycles to get all the soap out of the garment [I just rewash the bag without soap]. * Down Bags: use a mild powder soap or special down soap (available at outdoor stores). * Synthetic Bags: use a mild powder soap or special synthetic cleaning product. Drying: When moving your bag from the washer to the dryer, do so carefully by carrying it from the bottom. Tumble dry in a large commercial dryer on low heat. The dryer must be large enough for the bag to flop freely around. Drying will take several hours and your bag should be checked often to make sure it is not overheated. * Down Bags: as the bag dries, look for clumps of wet down and gently shake the bag to redistribute the down. Sometimes the down in the draft tube will need some gentle massaging during this process. * Synthetic Bags: as the bag dries, check for even distribution of fill material. Gently massage the bag if any bunching is detected. No-Nos * Do not use a top-loading washing machine (the agitator will destroy the baffles in the sleeping bag). * Do not use liquid soap or detergent [never never never never]. Do not use strong soap or detergent. * Do not use your home dryer (they have been known to melt holes in the fabric). * Do not lift your bag from one end when wet (lift the entire bag all at once from underneath). * Do not store in a stuff sack (use a larger storage sack which allows for air circulation). * Do not dry in the sun (the UV will damage the nylon).