Due to the impact of Public Law 99-457, many school psychologists will become increasingly involved in the psychological assessment of preschoolers. Since the law does not specify what assessment practices should be followed, current practices vary according to the setting, employer and practitioner. This study addresses the issue of an information need by establishing a database on current assessment practices. Information provided by school psychologists currently involved in the assessment of preschool children in public school settings would help define techniques specifically designed for this age group. To determine current preschool assessment practices, a survey was conducted of 100 school psychologists who work with preschool children enrolled in public school programs for early intervention in the New England region. Site visits to 12 preschool programs in Massachusetts and Connecticut were conducted to interview school psychologists regarding their preschool assessment practices. The survey endeavored to ascertain what assessment techniques are employed, which instruments are perceived to be most effective, and what the factors are that influence the selection of preschool assessment instruments. The role of the school psychologist as a member of an early intervention team was also examined. Results indicated a great variety of tools/techniques in use for assessment. The most frequently used tests/techniques were medical and developmental history, file review, interviews, classroom observation and norm-referenced tests; in sum, preferred measures sample a broader range of behaviors and are more useful in designing effective educational interventions. School psychologists, however, still need more knowledge of curriculum-based measures and dynamic assessment procedures. Results also indicated that tests are selected on the basis of their effectiveness. The most common rationale for selecting a particular tool cited was the match between referral question and intervention. The role of the school psychologist consisted primarily of assessment for classification/placement decisions. School psychologists and teachers were found to have the highest levels of involvement in assessment, followed by parental participation. Implications of the survey are discussed in terms of improving preschool assessment practices, as well as with respect to training of school psychologists