Introduction: school activity is characterized by high physical and mental demands. Any failure to adapt these requests to the possibilities of the age group can be associated with school failure. Material and method: the study was carried out on a group of 208 students from the 9th grade from a National College in Iasi (54 students), a National College in Pascani (80 students) and from an Economic High School in Iasi (74 students). A questionnaire regarding school activity and the causes of the phenomenon of school fatigue was applied. The results were processed using Pearson's chi-squared test. Results and discussions: The students are constantly preparing only for certain subjects (72.59%). The young people from the National College in Iasi stand out, as we find numerous answers of "I do not continuously prepare for any subject", so the calculated differences are statistically significant (p<0.01, ƒ=4, χ²=14.254). In most cases (65.86%) adolescents admit that they have been trained how to study only in certain subjects. In the students from the National College in Iasi there are few explanatory answers in all the disciplines, so the calculated differences are statistically significant (p˂0.001, ƒ=4, χ²=19,465). Young people study for pleasure only in certain disciplines (86.53%). At the National College in Iasi there are no students who study for pleasure in all disciplines, so the differences obtained are statistically significant (p<0.05, ƒ=4, χ²=11.072). Fatigue is often present in 58.65% of students, with significant differences between high schools (p<0.05, ƒ=4, χ²=11.807). The students attribute the occurrence of this phenomenon to the numerous subjects they have to study (55.76% -statistically insignificant differences), the large volume of homework (51.92% -significant differences) and insufficient sleep (48.55% -statistically insignificant differences). Conclusions: there are many factors that generate school failure that must be known and carefully assessed in order to reduce the frequency of this phenomenon.