To amend the Immigration and Nationality Act to establish a 24-month pilot program permitting certain aliens to be admitted into the United States to provide temporary or seasonal agricultural services pursuant to a labor condition attestation and to offset those admissions with temporary reductions in diversity and unskilled workers' immigrant visas.

Temporary Agricultural Worker Act of 1998 - Amends the Immigration and Nationality Act to establish a 24-month pilot program for the U.S. admission of temporary or seasonal agricultural workers based upon an employer labor condition attestation filed with the appropriate State agency. Sets forth program provisions. Offsets such admissions with temporary reductions in diversity and unskilled workers' immigrant visas. Establishes a trust fund in the Treasury to assure the return of such workers to their home countries.