Background: Ultrasound-guided percutaneous core needle biopsy (PCNB) has been used more and more frequently in diagnostics of pediatric solid tumors in our center. It is less invasive than an incisional biopsy. However, reports relating to its reliability in clinical practice are limited. Therefore, we aim to investigate the reliability of this technique in the pediatric population. Methods: A 7-year retrospective study including patients ≤ 18 years who underwent ultrasound-guided PCNB in our center was conducted. Children who received PCNB and final surgical treatment were included. Their medical records were reviewed. Final surgical pathological diagnoses were used as the gold standard to assess the diagnostic efficiency of PCNB. Results: A total of 169 children were included in our analysis. 87.0% of patients underwent PCNB for abdominal and pelvic masses. 79.1% of biopsies were performed under local anesthesia. There were 141 malignancies and 28 benign lesions confirmed by surgery. The most common malignancy was neuroblastoma (73), and the most common benign condition was fibromatosis. The diagnostic yield was 94.1%. The success rate of PCNB in determining benign and malignant conditions was 94.3% (150/159). Consistency between PCNB and final diagnoses was found in 143 cases, giving a total accuracy of 89.9%. The accuracy for diagnosing malignancies was 96.8% (122/126), and for benign diseases 87.5% (21/24). The difference was not statistically significant (p=0.0818). Severe complications occurred in 6 patients (3.5%). No evidence of needle tract dissemination was found. Conclusions: Ultrasound-guided PCNB is safe and effective in diagnosing pediatric solid tumors, especially in malignancies.