The purpose of this paper is to investigate the effectiveness of a combined phonology and expressive vocabulary screening test for preschool aged children. The use of screening tests within the field of Speech/Language Pathology has long been a standard practice when identifying children who need future diagnostic testing. Little development has occurred that combines tests which could reduce the amount of time spent with each child. This is important at a time when public school systems are attempting to comply with state and federal guidelines for screening preschool and kindergarten students in the areas of speech and language. It is particularly important for those states requiring screening procedures as opposed to referrals.Since the passing of Public Law 99-457, many states have implemented mandatory preschool programs for children who need special educational services. Although Indiana has not adopted a law requiring public schools to provide preschool services, the Commission on General Education of the Indiana State Board of Education and the Governor did approve Rule S-1 on August 25, 1978. Rule S-1 simply states that if a school provides education to nonhandicapped children aged three, four, five, eighteen, nineteen, twenty or twenty-one, the school shall make a free and appropriate public education program available to at least a proportionate number of handicapped children of the same age.Many schools throughout Indiana are developing preschool programs. The increased number of students with various handicaps will require additional professionals trained in specific areas of special education. One profession that has noted an increased caseload of three, four, and five year olds is the area of Speech/Language Pathology. As Speech/ Language Pathologists (SLPs) increase the amount of contact with these individuals, they also recognize the need for diagnosis and therapy of the preschool student.During the past five years the amount of research in the areas of test design and program development has increased. Researchers are studying the developmental norms of preschool children in order to develop new diagnostic and screening tests directed in these areas of performance. Expressive vocabulary and articulation tests are an essential part of a test battery. Although a complete test battery is needed for diagnostic purposes, SLPs have made it a standard practice to use screening instruments for identifying students in need of diagnostic testing. Professionals in particular educational settings have to provide standardized test results as evidence for the existence of disorders in addition to being required to submit Individualized Education Programs (I.E.P.s) or diagnostic reports for large numbers of children. A screening test allows the SLP to eliminate those individuals who do not require a complete battery of tests. A combined phonology and vocabulary test that requires a single response would make more efficient use of the SLP's time because of its ease in administration and scoring. Its simplicity would also allow for effective screening by speech aides and other paraprofessionals. There has been little interest in providing screening tools for combined phonological and vocabulary assessment. Presently there are few screening tests available for preschoolers that address both phonology and language. The purpose of this study is to construct a screening test of both phonology and expressive language that will accurately identify preschoolers who will require diagnostic evaluation. It is also the purpose of this paper to develop a screening test that is cost effective and easily administered and scored with four year old children in the school system or clinical setting.