The 2004 Beginning Postsecondary Students Longitudinal Study, 2004 Base Year (BPS:04) is part of the Beginning Postsecondary Students Longitudinal Study (BPS) program. BPS:04 is the base year of a longitudinal study that followed a cohort of students who enrolled in postsecondary education for the first time during the 2003-04 academic year, irrespective of date of high school completion. The 2003-04 National Postsecondary Student Aid Study (NPSAS:04) data provided the base-year sample for BPS:04. BPS:04 data are representative of all first time beginning students (FTB) enrolled in postsecondary institutions in the 50 United States, the District of Columbia, and Puerto Rico that were eligible to participate in the federal financial aid programs of Title IV of the Higher Education Act. Key statistics produced from the BPS:04 are issues as persistence and the effects of financial aid on subsequent enrollment. The cohort includes a sample of 23,090 students, a subset of students initially sampled for participation in NPSAS:04 and classified by their NPSAS institution as FTBs.