Mushrooms are some of the most sensitive foods in terms of temperature and spoil very quickly. Spoiled mushrooms are a real health threat, which is why we have to be very careful.
Mushrooms can last several days in the fridge, as long as they're stored properly. Put them in a paper bag, then in a larger plastic bag with holes in several spots - to allow the mushrooms to breathe.
Don't wash them or cut them before you put them in the fridge because this way they'll go bad even faster. The cold air in the fridge prevents mushrooms from going bad, at least for a few days - don't risk and keep them for more than 2-3 days though.
Do keep in mind that mushrooms take in the strong aromas around them, so keep them away from foods with a sharp aroma. If you have even the slightest doubt that your mushrooms have spoiled, best to throw them out.