Henry Helstoski, 75, a New Jersey Democrat who served in the U.S. House of Representatives from 1965 to 1977, died of prostate cancer Dec. 16 at a hospice in Wayne, N.J.

Mr. Helstoski represented the 9th Congressional District in Bergen County, N.J. He was an opponent of the war in Vietnam, became one of the first House members to call for the impeachment of President Richard Nixon and fought for environmental causes.

In 1976, he was indicted for taking bribes for introducing special legislation to help South American immigrants. Mr. Helstoski, who maintained his innocence, was defeated for election to a seventh House term. Despite the fact that he was never found guilty of the charges or even tried--the charges against him were dropped in 1980--he never resurrected his political career. He was twice defeated in attempts to return to Congress.

Mr. Helstoski was a native of New Jersey, where he graduated from Paterson College and received a master's degree from Montclair State College. He was an Army Air Forces veteran of World War II. He was a New Jersey school teacher and administrator and served as a city councilman and mayor of East Rutherford, N.J., before winning election to Congress in 1964.

After leaving Congress, he was a county government grants administrator, a substitute teacher, an accountant and a weekly newspaper publisher. He retired in the late 1980s.

Survivors include his wife, two daughters, a stepson, a brother, a sister and two grandchildren.