The newly developed computerized Constructive Multiple-choice Testing system is introduced. The system combines short answer (SA) and multiple-choice (MC) formats by asking examinees to respond to the same question twice, first in the SA format, and then in the MC format. This manipulation was employed to collect information about the two different formats with no significant increase in testing time. Two empirical studies were carried out to examine whether meaningful information can be obtained using this system. One hundred and twenty nine fifth grade students (11 years old) were tested on science in Study 1, and 82 college students were tested for grade in Study 2. In both studies, consistent with previous research, students attained higher score in the MC format, the correlation between the SA format and the MC format was high, and the item discrimination was higher in the SA format when compared with the MC format. The unique finding from this study is that there were some cases where students chose a wrong MC option, even though they typed in the correct answer for the SA part. Possible applications of the system are discussed.