An obituary in last Friday's editions of The Washington Post on Dr. R. Leonard Tillman, an assistant professor of pathology at Howard University who died on Jan. 23, inadvertently failed to refer to him as Doctor, the title by which he was known to his associates. The obituary stated, however, that Dr. Tillman earned a PhD at Howard in 1974.

R. Leonard Tillman, 45, an assistant professor of pathology at Howard University, died at his Washington home Tuesday of coronary arteriosclerotic heart disease.

Beside his work at the university, where he earned a PhD degree in 1974, Mr. Tillman was active in community affairs and politics, where, as he was fond of saying, he preferred "to work the vineyards," never seeking public office, but organizing at the grass-roots level and getting out the vote. All his life, a friend said, he had one foot in the street, and the other in academe.

City Council member John Wilson, with whom Mr. Tillman worked in putting together the reform Democrats movement several years ago, said yesterday: "He played an important role in this community just by making himself available to charities, projects and people."

For years, Mr. Tillman was active and visible in the Neighbors Inc. movement, the Takoma neighborhood group that ried so hard to keep the area racially mixed and functioning in the wake of the hot, mean summer of 1968.

He was a driving force, with Vincent DeGorrest, in the Afro-American Bicentennial Corp. (now the AfroAmerican Institute for Historic Preservation and Community Development) that, using a three-year grant from the Department of the Interior, got 68 black sites designated as historic landmarks. Before, there had been Five. More are ciming, DeGorrent said yesterday.

Mr. Tillman was born April 25, 1933, at Helm, Miss. The family moved to St. Louis in 1939, and Mr. Tillman attended public schools there.

He attended Fisk University in Nashville, receiving a B.S. degree in zoology in 1956. He spent the years 1953-55 in the Army, serving in Korea.

He received his master's degree in 1967 at Washington University in St. Louis, where he met and married the former Zanne Grimes. The marriage ended in divorce in 1977.

Mr. Tillman came to Howard University in 1967 as an instructor in pathology, and worked on his doctorate, which he received in 1974.

He contributed several articles to The Washington Post, none on pathology but one on how barbecuing is done the real way (up to 150 people would turn out for his July 4 barbecue).

Survivors include his mother, Annie Mae Tillman; two sons, Marc Leonard, 11, and P. Alex., 9; a brother, Cornelius Jr. of St. Louis, and three sisters, Ozzie Taylor of Los Angeles and Dorotha McHenry and Mae Jefferson, both of St. Louis.

The family has asked that in lieu of flowers, contributions be made to the Afro-American Institute.