Mrs. Sonia Dufey Day of Santiago, Chile, and Dr. Gustavo Day of Sarasota, Fla., announce the engagement of their daughter, Maribeth Dufey Day, to David Thomas Case, both of Raleigh, N.C.

He is the son of Mr. and Mrs. Frank Case of Suffolk.

Miss Day is the maternal granddaughter of Mrs. Elena Coulon Dufey of Santiago, and the late Mr. Daniel Dufey. She is the paternal granddaughter of the late Mr. and Mrs. Maximillian Day, who lived in Rancagua, Chile.

Mr. Case is the maternal grandson of Mrs. Maryvonne Brinkley of Suffolk, and the late Mr. Clarence Brinkley. He is the paternal grandson of the late Mr. and Mrs. Ben Case Sr., who lived in of Suffolk

The wedding will take place Saturday, July 17, in Raleigh.