For students, textbooks are a source of knowledge and an important learning material. For this reason, textbooks must contain appropriate content. In this research, our aim was to examine of biology subjects on secondary school 7th grade science textbook in terms of scientific content. The data were analyzed using document analysis. Based on criteria such as the book's scientific content, knowledge deficiency, erroneous information and misrepresentations, three experts in the field of biology were assigned the responsibility of reviewing the textbook. The findings of the research, categorized based on the chapters and units of the textbook included a discovery of scientific flaws, insufficient explanations on topics such as ''Systems of the Body'', ''Force and Energy'', ''Human's relationship with the environment'' and various other errors regarding the assessment questions. Recommendations therefore included a review of the said textbook in order to correct all such errors.