Patterns of enrollment at major U.S. research universities from 1965 to 1977 are examined in terms of headcounts, full-time equivalent students, and full-time and part-time students by type of institutional control, by sex, and by level of study. Data are presented for two groups of research universities: (1) the 51 leading universities in terms of federal financial support of academic science in at least two of the three academic years, 1972-73, 1973-74, and 1974-75; and (2) 47 universities from the list of the 100 leading institutions in terms of federal financial support in at least two of three years between 1972-73 and 1974-75. The universities must also have awarded at least 50 Ph.D.'s (plus M.D.'s), and have met other criteria. Findings include the following: the 51 group one major research universities have been characterized by relatively stable enrollments over the past 13 years; while total U.S. full-time enrollments were increasing by almost 4 percent a year during the 13 years, full-time students at the 51 universities increased at half that rate; the entire increase in enrollment at the 51 universities was accounted for by additional women students; the 47 group two research universities increased in enrollment at a slightly higher rate than the first group of research universities but considerably lower than the national increase; the greatest enrollment gain was in the 33 public institutions; the 47 universities showed strong and steady gains of women students; and undergraduate and graduate full-time enrollments at the 47 universities have been relatively stable but part-time enrollments at both levels have fluctuated. (SW)