Ed Headrick, who designed and patented the modern Frisbee, died Monday at his home in La Selva Beach, Calif. He was 78.

The cause was a stroke, said Scott Keasey, national sales manager for the Disc Golf Association. The association governs and supplies equipment for disc golf, a variation of golf invented by Mr. Headrick.

Mr. Keasey said that when Mr. Headrick accepted a job in 1964 as head of research and development for the Wham-O Manufacturing Company in San Gabriel, Calif., he was assigned the task of figuring out what to do with a warehouse full of unused plastic that had been intended for Hula-Hoops, another Wham-O product that came and went quickly.

His idea was to modify the Pluto Platter, a disc toy originally intended for children, into a sport for teenagers and adults. Walter Frederick Morrison had invented the disc and sold it to Wham-O in 1955. Mr. Morrison's name is on the patent granted in 1957, and he became rich from Frisbee royalties.