Richard A. Bloch, a co-founder of H&R Block and a champion of cancer patients, died early yesterday at his home in Kansas City, Mo. He was 78.

The cause was heart failure, said Linda McDougall, an H&R Block spokeswoman.

Mr. Bloch used his keen eye for business to build a family-owned bookkeeping company with 12 employees into America's largest preparer of tax returns. The expansion started in the mid-1950's, when with his brother, Henry, Mr. Bloch began advertising in a local newspaper to promote their company's tax preparation services.

The response was overwhelming, and in 1955 the brothers renamed their company H&R Block Inc., using their initials and an easy-to-pronounce spelling of their last name. They focused exclusively on tax preparation. Demand for the brothers' services soared as the Internal Revenue Service scaled back tax preparation services, Ms. McDougall said.

A year later, they opened seven offices in New York, and the company went public in 1962. By 1978, H&R Block offices prepared more than one of every nine tax returns filed in the United States, according to the company's Web site. Today, H&R Block has clients in 11 countries, including Canada, Australia and Britain.