Teacher aptitude should be considered in the selection of qualified teacher candidates. Those high in teacher aptitude have the potential to be more effective teachers. From this perspective, this study investigated: 1) teacher aptitude variables 2) issues involved in measuring teacher aptitude The validity of aptitude of an aptitude test is typically assessed through predictive or criterion-oriented validity. Teacher aptitude variables in two domains - cognitive and affective domain can be determined through analyzing the behaviors and personalities of good teachers. The concept of good teacher can be analyzed from three aspects: teacher education, teacher effectiveness, and characteristics of teaching profession. The possibility of measuring teacher aptitude can be further understood through analyzing academic aptitude tests, special aptitude tests, professional interest tests, characteristics tests for job placement, and attitude tests. The results and practical implications of the study are as follows: 1. Teacher Aptitude Variables a) Cognitive Domain The cognitive domain of teacher aptitude variables includes the knowledge of subjects and teaching methods. The teacher who has the knowledge of subjects understands the content of subjects, satisfies from intellectual persuits, and knows the teaching and learning process. The teacher who has the knowledge of teaching methods knows how to organize and explain subjects, how to make students participate in learning activities, and how to ask questions and motivate learning. b) Affective Domain The effective teacher is enthusiastic for teaching, warm to their students, fair and firm in the treatment of students, and has a positive self-concept. 2. The Possibility of Measuring Teacher Aptitude a) Aptitude is a term commonly used to refer to the potential for learning. Repeated studies have emphasized that the chance of succeeding in a certain job depends on certain/particular aptitudes and abilities. The term "aptitude test" has traditionally referred to a test measuring relatively homogeneous and clearly defined segments of ability. From this perspective, the term "teacher aptitude" can be used, and therefore there is the possibility that teacher aptitude can be measured. b) Aptitude tests includes general intelligence tests, multiple aptitude batteries, and special aptitude tests. Teacher aptitude tests can be considered a kind of special test because it is intended to predict success in the teaching occupation or in teacher training. c) Teacher aptitude tests can be considered from two aspects, that is, cognitive ability and personality. The teacher aptitude test of cognitive ability can be measured with the academic aptitude test such as the National Teacher Examination in America (NTE), which has recognized reliability and validity. The test is designed to measure general knowledge, professional knowledge, and special area knowledge. A variety of personality-related aptitude tests have been used in the teacher selection process. These include interest tests such as the Strong Voactional Interest Blank, characteristic tests such as the California Occupational Preference Survey, and attitude tests such as the Minnesota Teacher Attitude Inventory. Although it is difficult to measure different aspects of teachers` personalities. aptitude tests for teacher personality should measure these dimensions comprehensively rather than in isolation; any test used should measure a combination of interest, characteristics, and attitude to predict teacher aptitude. The above mentioned results and suggestions are intended to further the definition, measurement and refinement of teacher aptitude variables. Many studies should follow if these findings are available in practice. Although there are many restrictions in applying them in Korean settings because most of the available data were gathered in American studies, a number of parallels exist. The significance of this study