According to the Motley Fool, you should talk to as many lenders as you want. There is a special provision in the FICO credit scoring formula that allows you to shop around for the lowest mortgage rate. As long as all of your applications take place in a “normal shopping period,” say two weeks, it will count as a single credit inquiry for scoring purposes. A small difference in interest rates can save you thousands of dollars over the life of a 30 year mortgage, so it’s worth contacting at least a few lenders.