diff --git a/src/nf_modules/ont-guppy/main.nf b/src/nf_modules/ont-guppy/main.nf
index f5f89f0b89d965fd88a54d80c20576fe0ffecd28..b3e85df98678ada6acad54be103535384c3a96a3 100644
--- a/src/nf_modules/ont-guppy/main.nf
+++ b/src/nf_modules/ont-guppy/main.nf
@@ -53,7 +53,7 @@ guppy_basecaller --compress_fastq \
    --gpu_runners_per_device ${params.gpu_runners_per_device} \
    --num_callers ${params.num_callers} \
    --chunks_per_runner ${params.chunks_per_runner} \
-   ${params.config_file}
+   -c ${params.config_file}
 """
 }