The purpose of this article is to discuss major substantive errors that school personnel may make when developing students' Individualized Education Programs (IEPs). School IEP team members need to understand the importance of the procedural and substantive requirements of the IEP, have an awareness of the five serious substantive errors that IEP teams make, and know how to avoid errors. An assessment checklist, individualized education program goal development worksheet, and progress monitoring checklist are provided.