Background: Ultrasound-guided fine needle aspiration cytology (FNAC) is an essential diagnostic tool for detecting intra-abdominal masses, offering a cost-effective, safe, and accurate method for diagnosing benign and malignant lesions. Objective: This study aimed to establish ultrasound-guided FNAC as an accurate diagnostic method for intraabdominal solid masses and correlate FNAC findings with histological results. Methods: A prospective comparative study was conducted from November 2022 to January 2024 at Sher-e-Bangla Medical College Hospital (SBMCH), Barisal, involving 45 pediatric patients (24 males, 21 females) aged 3 months to 14 years. All patients underwent both FNAC and open biopsy. Data were analysed using SPSS v. 26 software to determine the accuracy of FNAC compared to histopathological findings. Results: Out of 45 cases, 10 (22.2%) were cytologically diagnosed as benign, including 4 (8.9%) non-neoplastic and 6 (13.3%) benign neoplastic. Thirty-three (73.3%) were diagnosed as malignant. Upon histological examination, 9 cases (20%) were confirmed benign, and 36 (80%) were malignant. One case showed a false negative (malignant histology, benign cytology). There were no false positives, with a sensitivity of 97.06% and a specificity of 100%. Conclusion: Ultrasound-guided FNAC is a highly accurate, non-invasive, and cost-effective diagnostic tool for intra-abdominal solid masses in pediatric patients, significantly reducing the need for surgical interventions.