Barney B. Welsh, 52, of Haverford, a senior member in the Philadelphia law firm of Ominsky, Welsh, Messa, Tanner & Giles, died of kidney failure Monday at Thomas Jefferson University Hospital.

Mr. Welsh, who specialized in civil litigation, practiced law in Philadelphia for 24 years before going into semiretirement in 1992 because of kidney disease.

He had joined the law firm about 20 years ago, and eventually became a shareholder in the practice.

A 1968 graduate of Villanova Law School, he clerked for a year for U.S. District Judge Charles Weiner in Philadelphia and then joined the law firm of Dilworth, Paxson, Kalish & Kauffman.

Mr. Welsh, who was born and raised in Philadelphia, had lived in Haverford for the last 13 years, moving there from Gladwyne.

He graduated from Olney High School and did undergraduate work in sociology at Temple University.

Mr. Welsh played baseball in high school and college. After high school, he tried out with the Phillies as a catcher but gave up a promising career in the sport to go to college, said Albert Ominsky, senior member of the law firm.

Mr. Welsh was a member of the American, Pennsylvania and Philadelphia Bar Associations, and the American and Philadelphia Trial Lawyers Associations. He was also a member of Sholom Aleichem, a Jewish social group, a member and former commissioner of the Bridlewilde Pony Club in Haverford, where he taught youngsters to ride, and was a former member of Radnor Country Club, where he played golf.

Mr. Welsh's kidney disease was diagnosed 14 years ago and he had received two kidney transplants.

He collaborated with his wife, Dr. Linda Buncher Welsh, who is a psychologist, and her co-author, Marian Bettancourt, on a book due out in April entitled, ''Chronic Illness in the Family, a Guide for Living.''

He learned to cope with the disease by ''transferring all his interests and activities from the practice of law to activities with his family and a personal interest in history,'' his wife said.

In addition to his wife, he also is survived by two children, Amanda and Adam; his mother, Gertrude Welsh, and a sister.

A funeral service will be held at 2:30 p.m. today at Goldsteins' Rosenberg's Raphael Sacks, 6410 N. Broad St., Philadelphia. Burial will be in Montefiore Cemetery, Philadelphia.

The family suggests contributions to the National Kidney Foundation or to Well Spouse, 610 Lexington Ave., Suite 814, New York, N.Y. 10020.