Immigrant populations are growing and permanently changing the demographic profile of the United States. Diverse cultural and linguistic backgrounds are manifested in the families in each community, imposing demands and challenges to agencies that provide services to them. A large population of immigrant families, especially first and second generations, experiences a process of acculturation while they are adapting to a new country. Recognizing this reality is crucial when culturally sensitive screening services are offered. Culturally sensitive assessments are not always available to families with young children, and psychometric properties of these instruments are not always thoughtfully studied. As a consequence, families might not receive reliable information about their children's skills. Psychometric examination of properties of screening tools is required to be responsive to the needs of diverse families. This study is aimed at examining the item equivalence of the Ages and Stages Questionnaires 3rd Edition (ASQ-3) for the 9, 18 and 30 month intervals and the cultural appropriateness, readability and utility of the Spanish ASQ-3 translation. Quantitative and qualitative techniques were used to determine item characteristic invariance across the English and Spanish versions and cultural appropriateness. Findings show that most of the ASQ-3 items function invariantly across language versions, indicating that these items are productive for gathering information, present an adequate hierarchy difficulty for order of items, and are properly using the response categories included on the tool. In addition, most of the values and qualities selected by parents are congruent with the content of activities included on the ASQ-3 items. Parents identified questions as useful for helping them to think more about their children's development. Accessible and sensitive instruments may facilitate parent participation in assessment, increasing the number of children correctly identified as having developmental risk regardless of ethnicity or linguistic background. Implications for practice and research are discussed, supporting cross-cultural studies on parent-completed questionnaires as an effective strategy for conducting screening and monitoring of young children's development in a context of cultural and linguistic diversity. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]