There were 58 seniors who received their diplomas on Sunday, June 1, 1980.
St. Mary's Graduating Class Roster of 1980
| Agee, Douglas Edward |
| Bandurowicz, Chris |
| Bassett, Laurence Mitchell |
| Borowiak, Jeffery Alan |
| Borowiak, Sandra Lee |
| Butka, Christine A. |
| Bunker, Daniel C. |
| Coan, Lawrence Wm. |
| Cherry, Steven |
| Coviak, Theresa Susan |
| Darge, Suzanne Marie |
| David, Kurt |
| Diebold, Mary Elizabeth |
| Essenmacher, Stephen |
| Distel, Elizabeth Mary |
| Francis, Laura Ann |
| Fosdick, Karen Maria |
| Gardner, Lynne |
| Holewinski, Richard James |
| Johnson, John |
| Jones, Robert |
| Karsten, Julie A. |
| Kozlowski, Laura Lynn |
| Kelly, Susan Marie |
| Land, Deborah A. |
| Kreger, Mark |
| LeBlanc, Terry |
| Lee, Lori L. |
| Liedel, Lydia Ann |
| Lilak, Donald Patrick |
| Makowski, Mark |
| Lochinski, John Joseph |
| Mason, Patricia M. |
| Mankowski, Tammie |
| Matelski, Jackie |
| McClusky, Geralyn Ann |
| Muzyl, Sandra Sue |
| Nowak, Patrick D. |
| O'Connor, Mary Bernadette |
| Nowak, Tina M. |
| Prusakiewiz, Cheryl May |
| Peck, Jacqueline Marie |
| Pytlowany, Kevin Michael |
| Quall, Brian L. |
| Richard, Ruth P. |
| Robb, Margaret Louise |
| Slivinski, Laurie Kay |
| Skop, Michael |
| Switalski, Angeline Mary |
| Stutesman, Jacqueline R. |
| Thulin, Charlotte |
| Tobin, James P. |
| Troy, Randy |
| Walsh, Patricia Ann |
| Walston, Wanda |
| Weaver, Jeffrey M. |
| Wilkinson, Kathleen Renee |
| Zaremba, Jerome Francis |