diff --git a/modules/umitools/dedup/main.nf b/modules/umitools/dedup/main.nf
index 07e6061d..56cb3a4b 100644
--- a/modules/umitools/dedup/main.nf
+++ b/modules/umitools/dedup/main.nf
@@ -26,6 +26,8 @@ process UMITOOLS_DEDUP {
     def prefix = task.ext.prefix ?: "${meta.id}"
     def paired = meta.single_end ? "" : "--paired"
     def stats = get_output_stats ? "--output-stats $prefix" : ""
+
+    if (!(args ==~ /.*--random-seed.*/)) {args += " --random-seed=100"}
     """
     umi_tools \\
         dedup \\