OBJECTIVE The present study assesses the safety of ultrasound (US)-guided percutaneous liver biopsies (PLBs) within pediatric liver allograft recipients, describes the pathological results according to early (≤12 months) and late (>12 months) posttransplantation periods, and analyzes the value of liver function tests (LFTs) and Doppler US variables in determining these results. METHODS A total of 219 US-guided PLBs in 85 pediatric patients with liver transplant (mean age 7 ± 5 years, range: 6 months to 18 years) performed between March 2005 and May 2012 were retrospectively evaluated at a single institution. Doppler US and LFT evaluation (including total bilirubin, alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, alkaline phosphatase) occurred within 1 day of early (n = 92, 42%) and late term (n = 127, 58%) posttransplantation biopsies. RESULTS The rate of major complications (hemorrhage requiring blood transfusion) was 0.91% (n = 2). The early versus late term biopsy results, respectively, included: cholestasis at 36% versus 18% (P = 0.003), minimal changes 16% versus 24% (not significant [NS]), acute rejection 13% versus 5% (P = 0.027), inflammatory diseases 15% versus 15% (NS), indeterminate acute rejection 11% versus 7% (NS), chronic rejection 4% versus 14% (P = 0.017), fibrotic diseases 4% versus 12% (NS), and other 0% versus 5% (NS). Neither LFT nor US variables were correlated with pathological outcomes. CONCLUSIONS The rate of complications in pediatric patients after US-guided liver biopsy is low. A range of pathological results exists between early and late posttransplantation liver biopsies. LFT and Doppler US findings are not predictors of pathological results.