The purpose of this study is to examine how the categorization skills of the 6th grade students in fractions are distributed and to determine the classification errors made by the students, along with the procedural errors of the students in fractions. The descriptive survey model, one of the quantitative research methods, was used in the study. In this study, 292 6th grade students from four middle schools in two districts of a province in Turkey participated. Developed by the researcher, the fraction operation skill test and classification skills identification test were used. The results showed that students had difficulty in distinguishing examples and characteristics of fractions and fraction types, and even though they partially succeeded in operations, they made procedural errors. The researchers recommend combining procedural knowledge with conceptual knowledge and explaining the basic characteristics of the concept by comparing examples with non-examples.