Can You Start a Sentence with "And" or "But"?

In our business writing classes, people often want an answer to this burning question: Is it acceptable to begin a sentence with the word and or but? The answer is yes. It is perfectly acceptable to start sentences with the conjunctions and and but. However, it is slightly informal. If formality is your goal, choose more formal language. Informal: But we hope to write an agreement today. (no comma