Since 1950s, teaching machines have changed a lot. Today, we have different ideas about how people learn, what instructor should do to help students during their learning process. We have adaptive learning technologies that can create much more student oriented learning environments. The purpose of this article is to present these changes and its effects on learning environment. First, after explaining the concepts of teaching machines and adaptive learning systems including their main features as well as integral components, similarities and differences between these technologies are discussed briefly. Then, following the discussion on weaknesses and strengths of adaptive learning systems, what instructional designers should consider in developing and using them are mentioned.