diff --git a/src/nf_modules/samtools/main.nf b/src/nf_modules/samtools/main.nf
index 75bbb514bbd61a945b913e3f91dba1d045827cba..d778e31f8c43d1b20d5b7aaeadc10bf270cb9aaa 100644
--- a/src/nf_modules/samtools/main.nf
+++ b/src/nf_modules/samtools/main.nf
@@ -178,8 +178,10 @@ process merge_multi_bam {
     tuple val(file_id), path("*_merged.bam*"), emit: bam
   script:
 """
-samtools merge ${bams} > \
-  ${bams[0].simpleName}_merged.bam
+samtools merge -@ ${task.cpus} \
+  ${bams[0].simpleName}_merged.bam \
+  ${bams}
+  
 """
 }