So many of the posts I've seen have been about people's leopard geckos going off food. The answers they get, and the solutions they find, are almost always the same. Check here before posting, and make sure none of these solutions are applicable. 1. How warm is your terrarium? Your gecko might be having trouble digesting the food. Try raising the temp. a few degrees, and see if that helps. Remember that leopard geckos rely on belly heat to help keep their body temperature up, and digest their food. This is the reason that many breeders/hobbyists prefer under tank heaters (UTH's) and heat mats to heat lamps. Also, make sure your gecko has a heat gradient (one part of the viv should be warmer than the other). 2. How long has it been since he/she stopped eating? It's normal for leopard geckos to go off of food every once and a while, particularly young geckos & geckos that you have recently brought home. They can get stressed after changing environments, and they probably won't eat much for a few days after being introduced to their new set-ups. Adults do the same thing every so often, so as long as they're eating normally again after a few days, you don't have to worry. 3. How much vit. D3 have you been supplementing with? Your leo needs D3 to process calcium, so your gecko's body produces all the vitamin D3 it needs. If you constantly dust your gecko's staple insect with Calcium + D3, your gecko may feel like it's taking in too much, and stop eating any food that has been dusted with it. Even with the extra, your gecko needs UVB of some kind to correctly process calcium. Supplement with PURE calcium (no phosphorous or D3) every feeding, and calc/vitamin D3 2-4 times a month. 4. Try enticing him/her with butter worms or wax worms. As phrased by StikyPaws312, they are the 'twinkies' of the reptile world. These both have little nutritional value, even when supplemented, and have a very high amount of fat, too much so to be a staple. Try giving one or two, then serve them along with normal meals for a few days. Gradually take them away, so your gecko doesn't become too attached and refuse anything else. 5. Switch up the diet. If you always feed meal worms or crickets, try switching to silkworms and roaches. There are many feeder insects, my favorites being the following: phoenix worms (black soldier fly larvae/calci-worms). These are very high in calcium, so they don't need to be supplemented, just with calcium+D3 every once and a while. Reptiles seem to find them very tasty, too! Whenever I get them, they're gobbled up. Silkworms are high in calcium, too, so you don't need to supplement as often as most other feeders. They are very soft bodied, and easy for herps to digest. And, just like phoenix worms, they taste really good, too. They can be a little high maintenance, though, so read up before buying them. I don't use roaches (considering it), but people who do say that they make excellent staple insects. My friend uses them, and loves them, and her leos do, too. 6. Is your leopard gecko able to access their food? Whenever I get crickets, I tear the back legs off. That makes them easier for my gecko to catch. They aren't the best hunters on the face of the Earth, and it can take them a while to find their food. If a cricket crawls under a hide, it can take the leopard gecko a while to it's there. If you don't put your meal worms in a dish, your gecko might not notice them. Uneaten meal worms turn into beetles, and your geckos terrarium provides an excellent place for them to grow. 7. Impaction Sand, calcium sand, any loose substrate can cause your gecko to become impacted. No, calcium sand is not digestible, even if it says so on the bag. Aside from that, it can cause other problems. It can irritate your geckos skin/eyes, or, in the case of colored sand, the dye can rub off on your geckos scales. If you feed your gecko inappropriately sized food, it can also become impacted. If your gecko is young, feeder insects with a hard outer shell (chitin) may be difficult to digest. Symptoms of impaction include substrate in the fecal matter. Symptoms also include constipation, and straining to excrete fecal matter. If you think that this might be the problem, you can read more about causes of impaction, symptoms, and treatment, readhere: http://hubpages.com/hub/Impaction. 8. Does your gecko have enough places to hide? Without enough hiding areas, your gecko may feel stressed and insecure, which can make it less hungry. I recommend having two-three hiding areas PER gecko: one on the cool side, one on the warm side, and a moist hide in the middle, towards the warm side. 9. Overfeeding If you feed your lizard too much, sometimes they will stop eating for a few days, to lose excess weight etc. Make sure that your gecko is eating again after two to three days, and to decrease the amount of food you offer. You should only give as much as your gecko can eat in twenty minutes. (If leo still has interest in food, or has trouble catching it, you can leave it in for a few more minutes.) 10. Illness If none of these things help/apply to your gecko, you might want to see a vet and have them check for any other illnesses. Metallic Bone Disease (MBD) and parasites are just two things that could put your pet leopard gecko off of food, as well as various infections. If this is the case, see your veterinarian as soon as possible. Hope this helped! If I forgot anything, please post and let me know.