Bone marrow failure (BMF) is a rare but life-threatening disorder characterized by hypocellular bone marrow, (pan)cytopenia in peripheral blood, and the absence of infiltrative disease of the bone marrow. It occurs as a result of acquired or inherited diseases. Acquired aplastic anemia (AA) is the primary cause of BMF in children and adults while inherited BMF syndromes (IBMF syndromes) are less common, but with a higher incidence in children than in adults. Early and accurate diagnosis of the disease is very important due to the specific treatment, monitoring and genetic counseling of patients and their families. This retrospective study presented the characteristics of patients and their clinical picture in the initial presentation of AA and IBMF syndromes, as well as patient survival depending on the therapy used and complications associated with the therapy. The study group consisted of 24 patients with aplastic anemia and 14 patients with IBMF syndrome. Out of a total of 24 patients with AA, 19 survived (79.17%). Primary bone marrow transplantation was successful in four out of five patients (80%). Primary immunosuppressive therapy (IST) showed a complete response in seven out of 18 patients (38.89%). Rabbit antithymocyte globulin and eltrombopag have not shown success in the treatment of AA. Lower doses of IST (administered since 2012) have led to a higher number of complete remissions compared to previously given higher doses (44.44% vs. 33.33%). Six out of a total of seven patients with Diamond-Blackfan anemia (85.71%) had a good response to corticosteroids, and one patient with a rare mutation underwent bone marrow transplantation. Two patients with Fanconi anemia had typical signs of the disease. A patient with Shwachman-Diamond syndrome had a characteristic clinical presentation without significantly elevated pancreatic enzyme levels, while a patient with Dyskeratosis congenita had an atypical clinical picture associated with a specific mutation.