What is Form 4029?

Purpose of form. Form 4029 is used by members of recognized religious groups to apply for exemption from social security and Medicare taxes. The exemption is for individuals and partnerships (when all the partners have approved certification).
Note. The election to waive social security benefits, including Medicare benefits, applies to all wages and self-employment income earned before and during the effective period of this exemption and is irrevocable for that period.

See the IRS Site for a copy of Form 4029 with instructions.