Nonresponse issues are investigated for the base year (1988) survey of the United States Department of Education's National Education Longitudinal Study of 1988 (NELS:88), a national probability sample of middle schools and eighth-grade students in the spring of 1988. The total eighth-grade enrollment for the NELS:88 sample of schools was 203,002; of these, 10,583 students were excluded due to limitations in their language proficiency or to mental or physical disabilities. As in the 1980 High School and Beyond (HSB) Study, the NELS:88 sample included about 70% initial selections and 30% replacement schools. NELS:88 non-respondents were 51.96% male and 43.07% female, with the gender of 4.96% not indicated, while NELS:88 respondents were 49.8% male and 50.2% female. Part 1 of this paper gives a brief overview of the study and its sample design, and outlines the main non-response issues, namely: (1) school and individual ineligibility for the study; (2) unit non-response, i.e., the fact that some schools and individuals declined to participate; and (3) item non-response in the student questionnaires and cognitive tests. Part 2 describes the methodology used for adjusting school level non-response in the NELS:88. Actual estimators are given, along with a method for evaluating the estimators and a method for deriving the estimate of response propensities for each school. Part 3 reports the results of an item non-response analysis of the student questionnaire data and the cognitive tests. Some comparisons are offered with non-response in the first year of the HSB survey. (SLD)