Short answer: Yes, you can be a Christian and believe in evolution. It is not a requirement for salvation, and I know of no creationist organization that says otherwise.
Long answer: Still yes, but it shows lack of commitment to the authority of God's Word because you're elevating man's "wisdom" above it. It also shows lack of knowledge about the theological implications of what such compromise entails. Then you have to make some choices.
I have encountered several people who were old Earth creationists or theistic evolutionists. After they became fully committed to Christ and grew in the Word, they became biblical creationists. Until then, are they unsaved?
As CMI has often stated, we regard evolution as contrary to Scripture, but Christians can still be saved despite believing in it (see related articles, below). Indeed, its founding chairman, the late Prof. John Rendle-Short, said he was a saved theistic evolutionist for 40 years before becoming a creationist.
So how can Christians hold to an anti-biblical doctrine? Here are a few things one should remember when considering whether a Christian can be an evolutionist:
(1) There are a range of biblical doctrines; and, while it’s important to be as consistent and biblical as we can, not every one is as “essential” as every other (even when we consider only true doctrines, as opposed to various misinterpretations). The Bible itself contrasts the “milk”, or “basic principles of the oracles of God”, with “solid food” for the “mature” (Hebrews 5).
You can read the rest of "Can Christian Believe Evolution?", here.No Christian is instantly (or even completely) mature. A brand-new believer shouldn’t be expected to have a reasoned position on the age of the earth … Few Christians have read the Bible through, so it would be asking a bit much to expect a new Christian …