diff --git a/gwaspy/imputation/impute5_impute.py b/gwaspy/imputation/impute5_impute.py
index ad45da0..65b51e3 100644
--- a/gwaspy/imputation/impute5_impute.py
+++ b/gwaspy/imputation/impute5_impute.py
@@ -62,7 +62,6 @@ def imputation(
                     --g {vcf['vcf']} \
                     --r {region} \
                     --buffer-region {buffer_region} \
-                    --out-gp-field \
                     --o {j.imputed_chunk['chunk.bcf']} \
                     --threads {ncpu}
                     """