diff --git a/src/toil_scripts/gatk_concordance/__init__.py b/src/toil_scripts/gatk_concordance/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/src/toil_scripts/gatk_concordance/gatk_concordance.py b/src/toil_scripts/gatk_concordance/gatk_concordance.py
new file mode 100644
index 00000000..cae32c1c
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+++ b/src/toil_scripts/gatk_concordance/gatk_concordance.py
@@ -0,0 +1,83 @@
+#!/usr/bin/env python2.7
+
+import argparse
+import multiprocessing
+import os
+import subprocess
+
+from toil.job import Job
+
+from toil_scripts import download_from_s3_url
+from toil_scripts.batch_alignment.bwa_alignment import upload_or_move, docker_call
+from toil_scripts.gatk_germline.germline import download_url, read_from_filestore_hc
+
+def build_parser():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-r', '--reference', required=True, help='Reference Genome URL')
+    parser.add_argument('-i', '--reference_index', required=True, help='Reference Genome index (.fai) URL')
+    parser.add_argument('-d', '--reference_dict', required=True, help='Reference Genome sequence dictionary (.dict) URL')
+    parser.add_argument('-1', '--eval_vcf', required=True, help='VCF file URL to evaluate')
+    parser.add_argument('-y', '--eval_label', required=False, help='Optional label for VCF file to evaluate, defaults to file name')
+    parser.add_argument('-2', '--comp_vcf', required=True, help='VCF file URL to compare against')
+    parser.add_argument('-z', '--comp_label', required=False, help='Optional label for VCF file to compare against, defaults to file name')
+    parser.add_argument('-o', '--output_dir', required=False, default=None, help='Local output directory, use one of this option or --s3_dir')
+    parser.add_argument('-3', '--s3_dir', required=False, default=None, help='S3 output directory, starting with bucket name, use one of this option or --output_dir')
+    return parser
+
+
+def batch_start(job, input_args):
+    shared_files = ['ref.fa', 'ref.fa.fai', 'ref.dict', 'eval.vcf', 'comp.vcf']
+    shared_ids = {}
+    for file_name in shared_files:
+        url = input_args[file_name]
+        shared_ids[file_name] = job.addChildJobFn(download_url, url, file_name).rv()
+    job.addFollowOnJobFn(concordance, shared_ids, input_args)
+    
+
+def concordance(job, shared_ids, input_args):
+    """
+    Evaluate concordance between two VCFs with GATK.
+    """
+    work_dir = job.fileStore.getLocalTempDir()
+    input_files = ['ref.fa', 'ref.fa.fai', 'ref.dict', 'eval.vcf', 'comp.vcf']
+    read_from_filestore_hc(job, work_dir, shared_ids, *input_files)
+
+    eval_name = input_args.get('eval_label', os.path.basename(input_args['eval.vcf']))
+    comp_name = input_args.get('comp_label', os.path.basename(input_args['comp.vcf']))
+    output = '%s_vs_%s.concordance' % (eval_name, comp_name)
+    command = ['-T', 'GenotypeConcordance',
+               '-R', 'ref.fa',
+               '-nct', input_args['cpu_count'],
+               '--eval', 'eval.vcf',
+               '--comp', 'comp.vcf',
+               '-o', output]
+
+    docker_call(work_dir = work_dir,
+                tool_parameters = command,
+                tool = 'quay.io/ucsc_cgl/gatk',
+                sudo = input_args['sudo'])
+
+    upload_or_move(work_dir, input_args, output)
+
+
+if __name__ == '__main__':
+    args_parser = build_parser()
+    Job.Runner.addToilOptions(args_parser)
+    args = args_parser.parse_args()
+
+    inputs = {'ref.fa': args.reference,
+              'ref.fa.fai': args.reference_index,
+              'ref.dict': args.reference_dict,
+              'eval.vcf': args.eval_vcf,
+              'eval_label': args.eval_label,
+              'comp.vcf': args.comp_vcf,
+              'comp_label': args.comp_label,
+              'output_dir': args.output_dir,
+              's3_dir': args.s3_dir,
+              'uuid': None,
+              # todo: this is req'd by gatk and by upload_to_s3
+              'cpu_count': str(multiprocessing.cpu_count()),
+              'ssec': None,
+              'sudo': False}
+
+    Job.Runner.startToil(Job.wrapJobFn(batch_start, inputs), args)