In the short run, no, your score will go down. But in the long run, it should help your score, otherwise there's probably no reason to file a bankruptcy. If you have a great credit score, you'll notice a very large decline if you file a bankruptcy. If your credit is already low because of missed payments or collection accounts, you'll notice just a small decrease.
But you have to think about what would happen if you didn't file. If you're going to go bankrupt, it's because bad things have already happened to your credit or will soon happen if you don't file. You might be making minimum payments right now to stay current, but you know you just can't hold on much longer. Instead of letting the black marks on your credit start rolling in, you're deciding to file, knowing it will hurt in the short run, but help you in the long run.
Fast forward several years and your credit score should have climbed significantly. Although a bankruptcy can stay on your credit report for anywhere from 7 to 10 years, it carries less weight the older it gets. Making payments on some loans, like mortgages, student loans, or very low-limit credit cards is the best way to build yourself back up.