Background and purpose Correlated with better follow-up of gliomas, cognitive disorders are increasingly studied. The aim of this study was to describe the cognitive disorders presented by these patients at baseline, before any treatment, and to evaluate the relations between cognitive disorders and return to work. Methods A detailed neuropsychological evaluation was administrated to 15 newly diagnosed patients with a grade II or III glial tumor before any treatment. Patients also completed the quality of life and depression scales. Results All patients in our study presented with at least one failed cognitive domain during the detailed examination, while the scores on the MMSE scale were within the norm. The most deteriorated functions were divided attention and episodic verbal and nonverbal memory. Moreover, a significant link was found between the number of failed cognitive functions and quality of life. Conclusion Cognitive disorders are frequent with glial tumors and impact patients’ quality of life. Simple tests of global cognitive status are not sufficient to detect cognitive difficulties in these patients. Consequently, detailed and adapted neuropsychological assessment is necessary, especially to detect deteriorated problems with memory, divided attention, or processing speed in this population.