In general, a credit increase will cause your score to go up, but only if it makes a significant difference in your debt to credit ratio. If you have a high percentage (say 90%) of your credit being used and a credit limit increase will take that percentage down below 70%, you will most likely see an increase in your score of up to 50 points or so. In most cases, the inquiry will not lower your score more than a few points, so it can be a good thing to request increases. But, if you request an increase and don't get it, your score will probably drop a bit from the inquiry.