1234, Main Street
Boston, MA 02123
<Recipient Address Goes Here>
Though I was very impressed with its work, I must turn down your invitation to join the <city name> Chamber of Commerce. I was very impressed by the group’s professionalism, ideas and commitment to helping local businesses grow, but since I am in the business of <your type of business>, I don’t think the Chamber would really help me grow.
I have a great deal of respect for what you and the other members are doing, and I wish you only the best of luck. If my business circumstances change, I will contact you about joining. Thank you very much for informing me about the Chamber. Good luck!
encl: <List of enclosed items goes here>