The purpose of this qualitative descriptive designed study was to explore how special education teachers from a private special education school with self-contained classrooms describe their experiences teaching and how they identify and select instructional strategies based on student's individual instructional and cognitive needs when teaching students with complex conditions in the Northeastern United States. Vygotsky's sociocultural theory was the theoretical foundation used to guide this research study. This study was guided by two research questions: How do special education teachers from a private special education school describe their experiences teaching students with complex conditions? And how do special education teachers from a private special education school identify and select instructional strategies for students with complex conditions based on their student's individual instructional and cognitive needs? The target population is private special education teachers teaching students with complex conditions. The two data sources utilized were semi-structured interviews and focus groups. The sample size was 15 interviews and two focus groups totaling 11 participants. The sample was collected using convenience sampling. Through thematic analysis six themes emerged; examples are: substantial demands and constantly moving variables requiring team work and flexibility, teaching skills for future adult outcomes and placement, differentiation of instruction and making proper modifications and accommodations, and various forms of instruction and assessments for differentiation of student levels. This study shows a greater understanding and insight into the intricacies of the role of special education teachers that teach students with complex conditions. Keywords: Special education, complex conditions, instructional strategies. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]