based on the regulatory frameworks in most countries, careful safety assessment based on comparison methods must be performed before the adoption and commercialization of GM crops and products. One of the safety assessments of GM plants is the comparison of key nutrients and metabolites between transgenic and non-transgenic lines. This study was designed to identify undesirable potential changes resulting from genetic manipulation (for example, as a result of the entry of foreign genes into the genome and new metabolite production) in transgenic potato resistant to potato tuber moth (Phetorima operculella). This process is known as substantial equivalence. This study attempted to examine total and soluble sugars such as sucrose, fructose and glucose in transgenic potato which were produced in Agricultural Biotechnology Research Institute of Iran. For this purpose, four transgenic lines (B2, B8, B11, B12) that have shown high levels of potato tuber moth resistance in bioassay tests were used. First, molecular analyses were performed on plant to be ensured of the presence of transgene, and the result of PCR showed that cry1Ab gene was present in all transgenic samples. The transgenic and control plants were transferred to greenhouse to produce the tubers. The harvested tubers were treated under light and dark conditions and then used for more analyses together with leaf samples. Evaluation of total sugar showed no significant differences between transgenic and control plants. Moreover, evaluation of soluble sugar showed that the contents of sucrose, fructose and glucose were not significantly different between transgenic and control plants. We conclude that according to evaluated components and regulatory rules of Codex, these transgenic potatoes are safe to use.