Wilms tumor is the most common childhood renal malignancy and the fourth most common childhood cancer. Many biomarkers have been studied but there has been no comprehensive summary. We systematically reviewed the literature on biomarkers in Wilms tumor to quantify the prognostic implications of the presence of individual tumor markers.We searched for English language studies from 1980 to 2015 performed in patients younger than 18 years with Wilms tumor and prognostic data. The protocol was conducted per PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Two reviewers abstracted data in duplicate using a standard evaluation form. We performed descriptive statistics, then calculated relative risks and 95% confidence intervals for markers appearing in multiple level II or III studies.A total of 40 studies were included examining 32 biomarkers in 7,381 patients with Wilms tumor. Studies had a median of 61 patients, 24 biomarker positive patients per series and a median followup of 68.4 months. Median percentages of patients with stages 1, 2, 3, 4 and 5 tumors were 28.5%, 26.4%, 24.5%, 14.1% and 1.7%, respectively, and 10.2% had anaplasia. The strongest negative prognostic association was loss of heterozygosity at 11p15, with a risk of recurrence of 5.00, although loss of heterozygosity at 1p and gain of function at 1q were also strongly linked to increased recurrence (2.93 and 2.86, respectively).Several tumor markers are associated with an increased risk of recurrence or a decreased risk of overall survival in patients with Wilms tumor. These data suggest targets for development of diagnostic tests and potential therapies.