The report presents advance data on selected social, economic, and demographic characteristics of persons of Spanish origin in the U.S. collected in the March 1976 Current Population Survey. The text, tables, and graphs cover size, composition, age, sex, residence, marital status, educational attainment, employment and occupation, income, and family characteristics. In March 1976, there were about 11 million persons of Spanish origin in the U.S.: an estimated 6.6 million of Mexican origin, 1.8 million of Puerto Rican origin, about 700,000 of Cuban origin, 800,000 of Central or South American origin, and 1.3 million of other Spanish origin. Of the 2.5 million families, 2.1 million were living in metropolitan areas. The median age was 20.9 years; about 13% were under 5 years of age. The proportion of single men was higher than that of single women. Women were more likely to be divorced or widowed than were men. Only 39% of the persons 25 years and over were high school graduates; about 19% of all persons of Spanish origin had completed less than 5 years of school. The labor force participation rate was 77% for men and 43% for women. About 2.2 million of the men were employed compared to 1.3 million of the women. The most prevalent occupation for men was that of operative, including transportation. The median income was $6,800 for men and $3,200 for women. One of every four families were below the low-income level. (NQ)