diff --git a/workflow/scripts/call_peaks_macs.py b/workflow/scripts/call_peaks_macs.py
index 1031bc8c9f616c58c6d622c2bc058ccd7d0bf6bc..c89c12eb7360e9efe10c23062be5cd09b2a8cdae 100644
--- a/workflow/scripts/call_peaks_macs.py
+++ b/workflow/scripts/call_peaks_macs.py
@@ -98,7 +98,8 @@ def call_peaks_macs(experiment, xcor, control, prefix, genome_size, chrom_sizes)
     # cross-correlation scores file
     with open(xcor, 'r') as xcor_fh:
         firstline = xcor_fh.readline()
-        fragment_length = firstline.split()[2]  # third column
+        frag_lengths = firstline.split()[2]  # third column
+        fragment_length = frag_lengths.split(',')[0]  # grab first value
         logger.info("Fraglen %s" % (fragment_length))