Management of children with trisomy 13 (T13) is controversial because of a paucity of evidence of the natural history, especially focusing on efficacy of treatment. There has been no report regarding natural history of children with T13 receiving intensive neonatal and pediatric treatment without cardiac surgery, although several reports have suggested efficacy of cardiac surgery. To describe the detailed and comprehensive natural history of children with T13 receiving intensive neonatal and pediatric treatment without cardiac surgery, we reviewed clinical information of 24 children with full T13 (15 boys, 9 girls) who were admitted to Nagano Children's Hospital from 1994 to 2016. Intensive neonatal and pediatric treatment without cardiac surgery was provided through careful discussion with the parents. We detailed accurate frequencies of complications, survival, underlying factors and the final modes of death, and psychomotor development of survivors. Unpublished complications including aortopulmonary window, pulmonary-ductus-descending aorta-trunk, biliary system abnormalities, eosinophilic enteritis, and neuroblastoma were described. Accurate frequencies of congenital heart defects (92%) and laryngomalacia and/or tracheomalacia (42%) were determined. The median survival time was 451 days and the 1-year survival rate was 54%. The major underlying factor associated with death was congenital heart defects and heart failure (63%) and the major final mode of death was heart failure (50%). Long-term survivors appeared to show slow but constant psychomotor development. Intensive neonatal and pediatric treatment without cardiac surgery for children with T13 is efficient for survival and psychomotor development, and could be a reasonable choice for parents having fetuses or children with T13.