This research brief looks at trends and issues in part-time undergraduate enrollment by summarizing the data available and comparing them to data on full-time students. Highlighted findings indicate that from 1970 to 1990 the number of part-time undergraduate students more than doubled and that most of this growth occurred during the 1970s. A profile of part-time students notes that they tend to be older than traditional age college students, that more women than men are part-time students, and that part-time students are most likely to attend public, 2-year institutions. In comparing part-time students to full-time students this review finds that part-time students are more likely to be independent of their parents, and that they are much less likely to receive financial aid than their full-time counterparts. Discussion of this finding points out that this is due in part to federal restrictions on financial aid which distinguish between part-time students who attend less than half time and those who attend more than half time. Included are a special section on part-time students at public 2-year colleges, discussion of implications, 6 end notes, 5 resources, and a 19-item bibliography. (JB)