This study examines the mathematical questioning of undergraduate Calculus I instructors for the purpose of detailing the ways in which instructors are using their questions. The emphasis is on verbal questions because of their in-the-moment value and ability to get students engaged in discourse. Calculus I is of particular interest because of its impact of the retention of Science, Technology, Engineering, and Mathematics (STEM) majors. I investigated the types of questions five instructors asked, the ways they used wait time, and the classroom setting during instruction. I found that the categories used to describe the types of questions posed in secondary mathematics classes (Boaler & Brodie, 2004) were appropriate for detailing the types of questions undergraduate instructors ask. Moreover, I found that the instructors asked a variety of question types in at least two in-class activities and most were just as likely to use wait time as they were to use no wait time. While there were similarities in the instructors' overall questioning, the cases stand alone as unique examples of the ways undergraduate Calculus I use their questions. [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.]