The purpose of this study is to discuss a wrong statement written about dimensional analysis in a physics text book prepared for the students who are studying in science, engineering and teaching undergraduate programs at universities and who have to take compulsory physics courses, to analyse the use of the text book including the wrong expression and its effects, and to define it again. Document analysis is used as the main method of data collection instrument in qualitative studies. The data of this qualitative study were gathered by examining the documents such as book or scientific paper published on the subject with a descriptive analysis method. The attention drawing statement in the physics textbook commonly used around the word is, "All quantities can be converted into length, time and mass units in the end. No matter how complex any physical quantity is, it is stated as algebraic combination of these three basic quantities." The most important findings of this study are as follows: the wrong description about dimensional analysis will not only be a book error, it will lead to misconceptions, and it will hinder learning dimensional analysis correctly and students' studying physics course.