Background: Malnutrition is a common complication in children with cancer. Cancer treatment and malnutrition can disrupt gut microbiome diversity and composition. This study aims to compare the dietary intakes between children with solid tumors post-chemotherapy and healthy controls, and investigate associations between the dietary intakes and the gut microbiome. Procedure: Children (7-18 years) with solid tumors were recruited during year 1 after the completion of chemotherapy from Children’s Healthcare of Atlanta, Atlanta, Georgia. Healthy controls were recruited via flyers. Children completed the Block Kids Food Screener for dietary intakes in the past week. Fecal specimens were collected and processed for the gut microbiome. QIIME2 and Mann-Whitney U tests were conducted to answer the research questions. Results: Forty-nine children (25 cancers vs 24 controls) were analyzed. Two groups had no differences in age, race, sex, and body mass index. Children with solid tumors reported significantly higher mean daily intakes of macronutrients: calories, protein, fat, carbohydrate, and fiber, and antioxidant nutrients (vitamin E, vitamin C, and selenium) than controls. Children with adequate vitamin B6 had a higher Chao1 diversity index than children with inadequate or excessive intake (P = 0.0004). Children with excessive selenium intake had a trend of higher Pielou’s_e index than children with inadequate intake (P = 0.091). Conclusion: Children with cancer reported significantly higher intakes of macronutrients and antioxidant nutrients than healthy children, but no differences in major energy ratios. Macronutrients, particularly antioxidant nutrients, were associated with disruptions of the gut microbiome in children with solid tumors.