Objectives of study: The adolescent population signifies the transitory period where the frequent occurrence of different histopathological lesions in patients with nephrotic syndrome (NS) is different from that seen in young children as well as that seen in adults. This study aimed to analyze the clinical features and histopathological spectrum of adolescent-onset NS. Material and methods: We retrospectively evaluated clinical features, biochemical investigations and histopathology of 103 children with idiopathic NS referred to the Pediatric Department, County Hospital of Târgu-Mureş. Fourteen patients with congenital-, infantil- and secondary NS were excluded from this study. Results: The patients were divided into 2 groups: in group A we included 69 patients diagnosed with NS diagnosed before 10 years-old, with a median age of 3.76±1.96 years, majority males (59.42%) and presenting the pure form of NS. On the other hand, in group B we included 20 adolescents having the median age at the onset of the disease 13.61±2.18 years, with equal distribution of the sexes and presenting the impure form in 65% of cases. The majority of the patients in both groups (68.11% and 70% respectively) responded to steroid therapy. The commonest histopathological subtype in both groups was focal segmental glomerulosclerosis. Conclusions: The incidence of nephrotic syndrome has increased in the last years. The impure form of NS is more frequent in the adolescents than in younger patients. Adolescents with impure and steroid-resistant NS at presentation have other lesions than minimal change disease. The early genetic diagnosis in NS is important for proper clinical management of the patients, prognosis and genetic counseling of the families.