diff --git a/nifti2/nifti2_io.c b/nifti2/nifti2_io.c
index 58b20841..43a26f71 100644
--- a/nifti2/nifti2_io.c
+++ b/nifti2/nifti2_io.c
@@ -8826,9 +8826,11 @@ nifti_image *nifti_image_from_ascii( const char *str, int * bytes_read )
                nim->nifti_type = NIFTI_FTYPE_NIFTI2_2 ;
      }
      else if( strcmp(lhs,"header_filename") == 0 ){
+       free(nim->fname) ;   /* the attribute may appear more than once */
        nim->fname = nifti_strdup(rhs) ;
      }
      else if( strcmp(lhs,"image_filename") == 0 ){
+       free(nim->iname) ;
        nim->iname = nifti_strdup(rhs) ;
      }
      else if( strcmp(lhs,"sto_xyz_matrix") == 0 ){
diff --git a/niftilib/nifti1_io.c b/niftilib/nifti1_io.c
index 1992b188..0580c629 100644
--- a/niftilib/nifti1_io.c
+++ b/niftilib/nifti1_io.c
@@ -6706,9 +6706,11 @@ nifti_image *nifti_image_from_ascii( const char *str, int * bytes_read )
                nim->nifti_type = NIFTI_FTYPE_ASCII ;
      }
      else if( strcmp(lhs,"header_filename") == 0 ){
+       free(nim->fname) ;   /* the attribute may appear more than once */
        nim->fname = nifti_strdup(rhs) ;
      }
      else if( strcmp(lhs,"image_filename") == 0 ){
+       free(nim->iname) ;
        nim->iname = nifti_strdup(rhs) ;
      }
      else if( strcmp(lhs,"sto_xyz_matrix") == 0 ){