Nowadays, maintaining health and improving the quality of life are concerns of human society. Health-promoting behaviors in childhood can pave the way for a healthier life in adulthood. Therefore, planning and attracting the attention of the scientific community to this subject is necessary to reduce the losses caused by the burden of diseases and its impact on the family and community health. On the other hand, it is clear that interventions will be more effective and less costly if they are carried out at an earlier age. Therefore, factors affecting pregnancy for maternal and fetal health, breastfeeding, and proper nutrition in the first 2 years after birth should always be considered. The contradictory effects of cyberspace on children's physical and mental development are other areas of concern in this era. With current human knowledge, planning for the first 1000 days of life is very vital. In this national congress, our goal was to achieve a collective effort to improve the quality of care during this period. The congress was held on December 13-15, 2023 in Sari, Iran. The topics included: Infectious Diseases, Neurology, Psychiatry, Oral and Dental Health, Radiology, Nutrition, Hematology and Oncology, Immunology and Allergy, Nephrology and Urology, Critical Care and Pulmonary, Glands and Endocrine, Neonatology.