You didn't mention how old your daughter is, so I'm going off the fact that she's crawling. That is a very hard age to put on weight. Gaining is good. I get frustrated with the doctors sometimes when the tell me to make sure my son gains weight and when we do everything we can and he doesn't, they tell me he's fine. We, too, fight for every ounce and are grateful to be any where on the growth chart. We've battled failure to thrive and all with him. I wouldn't worry if the doctor's aren't worried. It's great that she's crawling and getting into things. She is probably just burning off everything she eats. After a while, you'll probably see that she has grown up, just not out. Our son would get super skinny at those times. He now, at almost 3 has reached between 10 and 25 percentile, depending on the visit. His height is around 50%, so still way skinny. I would just offer a lot of snacks and such. We did very high fat - at least as much as he tolerated, which wasn't much - and about the only thing he drank or drinks is whole milk. Carnation Instant Breakfast, 1 serving to 10 oz. whole milk, is a common formula substitute and we did that until he was almost 2. It has 10 calories more per ounce than dose formula. You're at a really hard stage for weight gain, and walking (running) is only going to make it harder. As if it hasn't been already, be prepared for an uphill battle. There were times until age 2 that our son would grow significantly taller, yet loose weight because of his constant activity. I think 5 ounces in 3 months sounds great for a struggling baby. We went 6 months (age 4-10 months) with nothing! Hang in there. I know it's hard not to worry. If the doctor isn't concerned, relax. If you have concerns about the doctor, by all means, see someone else for a second opinion. Our doctor puts stock into the fact that our son is bigger as far as how the clothes fit, even if it can't be measured medically, so the fact that you perceive growth is reassuring. Enjoy keeping up with her and don't worry! :)