Objective:To summarize the clinical features of neuroblastoma (NB) with bone metastasis in infants and the prognostic factors.Methods:A retrospective analysis was performed on 32 patients aged ≤12 months who were enrolled in Beijing Children′s Hospital, Capital Medical University from January 2010 to December 2019 and had imaging findings suggesting signs of distant bone metastasis.The control group was included NB children, aged ≤12 months, who were admitted to Beijing Children′s Hospital, Capital Medical University during the same period, without signs of distant bone destruction.The clinical manifestations and auxiliary examinations of infants with bone metastasis were summarized, and the efficacy evaluation and survival analysis of infants with regular treatment and follow-up were conducted until December 31, 2020. Kaplan- Meier survival analysis was used for prognostic analysis, and Log Rank test was used for univariate prognostic analysis. Results:There were 32 NB infants with bone metastases, involving 12 males (37.5%) and 20 females (62.5%), accounting for 16.0% (32/200 cases) of infants diagnosed with NB du-ring the same period.The median age of onset was 9 (4.5-12.0) months.The main primary site included the retroperitoneal and adrenal region in 24 cases(75.0%) and mediastinum in 3 cases (9.4%). Among the 32 cases, 14 cases (43.8%) had simple bone metastasis, 19 cases (59.4%) had distant lymph nodes, 18 cases (56.3%) had bone marrow, and 3 cases (9.4%) had intracranial and meningeal metastasis.Bone metastasis mainly occurred in the skull, with 11 cases of single bone metastases and the remaining with 2 or more bone metastases.Compared with 168 NB infants without bone metastasis, the prognosis of those with bone metastasis was significantly worse [3-year overall survival(OS) rate 97.6% vs.82.7%, P=0.001]. Univariate analysis showed that the prognosis of NB children with bone marrow metastasis, meningeal and intracranial metastasis, MYCN gene amplification, and high-risk group was poor (all P<0.05). Two patients returned to the local hospital for treatment after diagnosis.A total of 30 children were recruited for efficacy evaluation and prognostic analysis.Twenty-nine children underwent surgery, of which 6 cases received surgery before chemotherapy and 23 cases received surgery after chemotherapy.One case received chemotherapy only.The mean course of chemotherapy was 6.2 (4-13) times.One case was treated with radiotherapy, 1 case was treated with Metaiodobenzylguanidine (MIBG) therapy, and 1 case was treated with stem cell transplantation.A total of 18 cases (62.1%) event-free survived, and 12 cases (40.0%) had a mean event at 7 (1.5-32.0) months.Among them, 7 cases survived and 5 cases died (16.7%). The expected 3-year event-free survival rate and OS rate were 57.1% and 82.7%, respectively. Conclusions:The most common sites of infant NB metastasis are bone and bone marrow, and the most common sites of bone metastasis are skull.Infants with bone metastasis had a worse prognosis than those without bone metastasis, and infants with bone and bone marrow metastasis had a worse prognosis than infants with single bone metastasis.