Hank Ketcham, who fathered the cartoon character Dennis the Menace, the freckle-face scamp in droopy overalls whose mischievous childhood has endured for 50 years and amused a worldwide audience, died yesterday at his home in Carmel, Calif. He was 81.

In March a half-century of the publication of Dennis the Menace cartoons was celebrated, with the panel running in 1,000 newspapers in 48 countries and 19 languages.

''Mischief just seems to follow wherever Dennis appears, but it is the product of good intentions, misdirected helpfulness, good-hearted generosity and, possibly, an overactive thyroid,'' Mr. Ketcham wrote in his 1990 autobiography, ''The Merchant of Dennis the Menace.''

''But what a dull world it would be without any Dennises in it! Peaceful, maybe -- but dull.''

Only yesterday, Dennis, holding a jar containing a spider, told the neighbor girl: ''Stop screamin', Margaret! You'll scare him!''

In one of the early cartoons, Dennis stood between his mother and her tea guest with a fur coat draped over his arms, saying, ''I showed Mrs. Taylor your new fur coat, Mom, but she didn't turn green like you said she would.'' In another cartoon, a defiant Dennis told Mom: ''Don't shout at me! I'm not your husband!''

Besides the newspaper cartoons, the fictional Dennis -- inspired by Mr. Ketcham's little boy of the same name, who grew up to live a troubled life -- gave rise to books of cartoons, a musical, a television series, a film and the Dennis the Menace Playground in Monterey, Calif.

On the occasion of the 50th anniversary of his cartoon creation, Mr. Ketcham told The Associated Press: ''It's a joyful pursuit realizing that you're trying to ease the pain of front-page news or television. There's some bright little spot in your day that reminds you that it's fun to smile.''

Mr. Ketcham was pursuing a career as a freelance cartoonist in October 1950, when his first wife, the former Alice Mahar, burst into his studio to complain that their 4-year-old, Dennis, who was supposed to be napping, had instead wrecked his bedroom.

''Your son is a menace,'' she shouted.

Only five months passed before 16 newspapers began carrying the adventures of the impish but innocent ''Dennis the Menace.'' By May 1953, 193 newspapers in the United States and 52 abroad were carrying Dennis's antics and remarks to 30 million readers.

As the popularity of the cartoons swelled, Mr. Ketcham remained unaware of their impact for some time. But later his travels prompted him to say, ''Holy smoke, how come everybody knows about Dennis?''

A few years after the birth of ''Dennis the Menace,'' Mr. Ketcham said, ''This little slave driver has kept my nose to the drawing board continuously, while doing nothing himself but annoy the neighbors, startle his parents, confound his teachers and in general have himself a rousing good time.''

The real-life Dennis was 12 in 1959 when his mother died of a drug overdose. Mr. Ketcham took the boy to live with him in Geneva, where he spent some 20 years before moving back to California in 1977.

But Dennis had difficulty with his schooling and was sent to boarding school in Connecticut while Mr. Ketcham remained in Switzerland with his second wife, the former Jo Anne Stevens. The marriage ended in divorce.

Dennis Ketcham served in Vietnam, suffered post-traumatic stress disorder and had little contact with his father.

''He's living in the East somewhere doing his own thing,'' Mr. Ketcham said in March. ''That's just a chapter that was a short one that closed, which unfortunately happens in some families.''

Mr. Ketcham is also survived by his third wife, the former Rolande Praepost and their two children, Scott and Dania, all of Carmel, Calif.

Henry King Ketcham, a son of Weaver Vinson Ketcham and the former Virginia Emma King, was born in Seattle on March 14, 1920. In his autobiography, Mr. Ketcham wrote that the seed of his career was planted when an advertising artist who was a friend of his father came to their house and sketched the comic strip characters Moon Mullins, Andy Gump and Barney Google. Mr. Ketcham said he couldn't wait to borrow the man's ''magic pencil.'' He was then no more than 6.

He dropped out of the University of Washington in his freshman year in 1938 to pursue his childhood dream. He found work as an animator for Walter Lantz, the creator of Woody Woodpecker, and later at $25 a week for Walt Disney, applying his talent to animated films like ''Fantasia'' (1940), ''Pinocchio'' (1940) and ''Bambi'' (1942) before serving in the Navy in World War II and drew cartoons for military posters, training purposes and War Bond sales. Afterward, he moved to Carmel to devote himself to freelance cartooning.

In 1994 he retired from producing ''Dennis the Menace'' cartoons, which continue at the hands of a team of artists and writers, and devoted himself to paintings, oils and watercolors that depicted jazz musicians, women's faces, other cartoonists and golfing scenes.

Mr. Ketcham once recalled his first journey abroad, in 1959, to the Soviet Union for an exchange of cartoons. The trip prompted the Central Intelligence Agency to enlist him to draw anything that might be useful to the United States in those cold war days.

''We were flying from Moscow to Kiev, and it was during the day and I looked out the window and I saw some shapes,'' Mr. Ketcham said.

''I had my sketch book, and I would put them down, and the flight attendant would walk by, and I would put a big nose and some eyes and make the whole thing into a funny face. So I had a whole book of funny-face cartoons at the end that I didn't know how to read.''

Long afterward, Mr. Ketcham encountered a C.I.A. official and mentioned his adventure, saying: ''I'm sorry. I didn't have anything to report.''

To which the official replied, ''Yeah, I know, Hank, we haven't sent any more cartoonists on any more missions.''

Henry K Ketcham