Wait for the diploma to arrive in the mail if you have just graduated. The Registrar's office at the University of Massachusetts will mail your diploma within six weeks of your graduation date. According to the Registrar's website, if you graduated in February they will mail your diploma in May; if you graduated in May they will mail your diploma in August; if you graduated in September they will mail your diploma in November.
Check the address information that the registrar's office has for you in the SPIRE Student Center Graduation information. If the address is incorrect and it is less than six weeks after your graduation date, change it on the SPIRE website and it will be mailed to you.
Call the Registrar if you have lost your diploma or if you believe it was mailed to the wrong address. As of 2011, the number is (413) 577-3058 and their business hours are Monday through Friday, 9:00 a.m. to 5:00 p.m.
If you prefer to write, mail a letter requesting another copy. The letter should contain your name, student ID or Social Security number, date of graduation and your date of birth. Mail the letter to:
Office of the University Registrar
Attention: Senior Staff
University of Massachusetts Amherst
207 Whitmore Administration Building
181 Presidents Drive
Amherst, MA 01003-9313