Ella T. Grasso, 61, a Democrat who was governor of Connecticut from 1975 until she resigned Dec. 31 because of ill health, died yesterday in Hartford of cancer.

She was the first woman governor who had not been preceded in office by her husband. Or, as Gov. Grasso once put it, she was the nation's "first lady governor who was not a governor's first lady."

Gov. Grasso was born to Italian immigrant parents and was reared in the political system of Connecticut's legendary John M. Bailey, longtime state chairman of the Democratic Party and national party chairman during the 1960s, guided her rise to power.

Gov. Grasso served more than 25 years in elective office and never lost and election. She spent four years in the state legislature, 12 years as Connecticut's secretary of state, then was a member of the U.S. House of Representatives from 1971 to 1975. She was elected governor in 1974 and re-elected four years later.

When she first assumed office, she took leadership of a state confronted with financial difficulties and the specter of recession.

Gov. Grasso fought to hold down spending while resisting the imposition of a state income tax. To buttress her policy, she rejected a $7,000-a-year increase in her own pay. Advised that this was not legal under state law, she accepted the pay increase, then returned the amount of the raise to the state treasury.

When she and other state officials traveled to New York City to find buyers for $100 million in Connecticut bonds in 1976, they traveled by Greyhound bus.

She began losing popularity as her first term drew near its close because she was forced to retrench economically, curtail some state services and lay off state workers.

Gov. Grasso regained a measure of popularity during the blizzard of February 1978 when she set up a state command center, traveled by helicopter to trouble spots throughout the state and trudged through snow drifts on her fact-finding mission. She eventually became known throughout much of the state as "Mother Ella."

In 1978, Robert Killian, the state's lieutenant governor, ran against Gov. Grasso in the Democratic primary. Gov. Grasso pointed out that under her governorship, 260 new businesses had been attracted to the state and that the condition of Connecticut's treasury had improved from a $70 million deficit to a $95 million surplus.

She defeated Killian by a 2-to-1 margin and whipped her Republican challenger in the November election, Ronald A. Sarasin, 613,000 to 422,000. c

In April 1980, Gov. Grasso underwent surgery for ovarian cancer. In late November, she was hospitalized with phlebitis and it was discovered that the cancer had spread to her liver. Doctors determined in December that the cancer by then had involved her intestinal tract. On Dec. 4, Gov. Grasso announced that she lacked the "stamina or the endurance" to continue in office and resigned, effective the end of the year.

Known for her vivacious personality and firm beliefs, she became well known outside her own state. Gov. Grasso was a member of the Democratic National Committee from 1956 to 1958. She served on the platform committee at the Democratic National Convention in 1960, and cochaired the resolutions committees at the 1964 and 1968 conventions. She was chairman of the New England Governors Conference in 1977.

At the 1968 convention, she helped push through a minority report that opposed continued American involvement in Vietnam. She also was one of those who walked out of the convention to protest the tactics used by the Chicago police department to quell demonstrations.

During her years in Congress, she fought for the expansion of minimum wage laws, increased veterans benefits, greater funding for Social Security and health programs for the elderly, and voted against funding for the Supersonic Transport.

Born Ella Rose Giovanna Oliva Tambussi in Windsor Locks, Conn., Gov. Grasso was the daughter of parents who had come to this country from the Piedmont section of Italy. Her father was a baker, she recalled, "so we always had enough to eat." Gov. Grasso characterized her mother as a woman who was a "great reader" and pushed the future governor on top that pursuit.

After attending Catholic schools in Windsor Locks, Gov. Grasso won a scholarship to the Chaffee School in Windsor, Conn. She then went on to Mount Holyoke College in South Hadley, Mass., from which she graduated magna cum laude in 1940. She studied sociology and economics and was elected to Phi Beta Kappa. She earned a master's degree there in 1942 and was a statistics instructor before returning to Connecticut.

During World War II, she was assistant state research director for the federal War Manpower Commission. Her first move into politics was to join the League of Women Voters in 1943. She was elected to the state house in 1952.

During her years as Connecticut's secretary of state from 1959 to 1971, she turned her first-floor office in the Capitol in Hartford into a "people's lobby" and encouraged citizens to visit her and air grievences. She also was chairman of the Democratic state platform committee during these years.

A talented and gifted speaker, Gov. Grasso spoke fluent Italian. She was a member of the Connecticut Council of Catholic Women and the Order of the Sons of Italy.

She was the wife of Thomas A. Grasso, a retired school superintendent, whom she married in 1942. They had two children, James and Suzanne, both of whom are teachers.