A bat that is found indoors is most likely to be a crevice-dwelling species. Although the fur color of crevice-dwelling bats varies, it is usually a shade of gray or brown. These bats are often lost youngsters or migrating bats. Oftentimes they will find their way out through an open window after dark, if the room the bat occupies is closed off from the rest of the house. If this is not an option, and if you feel confident that you can move the animal without physically touching it or injuring it, proceed to step one. Otherwise, proceed to step five.

1. Wait until the animal is motionless. A bat that is flying is almost impossible to catch, and you have a greater chance of injuring the bat if you attempt to capture it while it is airborne. In addition, bats that are caught while flying frequently panic and attempt to bite. Be patient. Wait until the bat lands and is still, and then proceed to step 2.
2. Contain the bat. Quietly approach the bat, and wearing thick gloves or using a thick towel, gather the bat up (holding it securely but not tightly) and place it into a box or similar container with a lid. Or instead, simply place a box, waste can, coffee can or similar object over the bat where it has landed. Then, take a piece of cardboard and gently slide it between the box and the surface the bat is on (i.e. floor, wall or ceiling). Keeping the cardboard in place, gently turn the container right side up. If the bat is captured during the day, proceed to step 5. If the bat is captured at night, proceed to step 3. Note: Do not place the bat in a bird cage or container with small openings. Bats are very intelligent and can easily squeeze through a 1/4 x 1/2 inch crack.
3. Release the bat outdoors at nightfall. Once the bat has been captured, take the container outdoors. Take a flashlight and a towel or gloves with you in case the bat has problems flying away. Find an elevated area (such as a deck or ladder), lift the box over your head, and tilt it to the side so the bat can fly out (the bat will not be able to fly out of a grounded container in a vertical position). Proceed to step 4. (Note: Do not release the bat during the day or during cold or bad weather. Instead, proceed to step 5).
4. Watch it leave. Use the flashlight to watch the bat fly away. If the bat does not fly away, or attempts to fly but seems unable to, it is likely that is has an injury or illness. It may be a disoriented juvenile, or it may simply be dehydrated or starved from being trapped indoors. If this is the case, use the towel or gloves (not bare hands) to gather the bat up. Keep the bat in the closed container and put it in a safe place that is free of children, pets, fire ants or other hazards, and proceed to step 5. 
   Note: It is not safe to attempt care for the bat on your own - bats should only be cared for by trained, vaccinated individuals. Furthermore, in order to survive, bats in this condition may need injections of electrolytes in addition to specialized food and caging.
5. Call a local wildlife rehabilitator for assistance. If you need help locating a wildlife rehabilitator or bat worker in your area please see Local Rescue.