diff --git a/c/mapping/mapper_filter.c b/c/mapping/mapper_filter.c
index 08ffeafa7..b42d62e41 100644
--- a/c/mapping/mapper_filter.c
+++ b/c/mapping/mapper_filter.c
@@ -8,11 +8,12 @@
 
 typedef struct _mapper_filter_state_t {
 	lrec_evaluator_t* pevaluator;
+	int do_exclude;
 } mapper_filter_state_t;
 
 static sllv_t*   mapper_filter_process(lrec_t* pinrec, context_t* pctx, void* pvstate);
 static void      mapper_filter_free(void* pvstate);
-static mapper_t* mapper_filter_alloc(mlr_dsl_ast_node_t* past);
+static mapper_t* mapper_filter_alloc(mlr_dsl_ast_node_t* past, int do_exclude);
 static void      mapper_filter_usage(FILE* o, char* argv0, char* verb);
 static mapper_t* mapper_filter_parse_cli(int* pargi, int argc, char** argv);
 
@@ -25,8 +26,9 @@ mapper_setup_t mapper_filter_setup = {
 
 // ----------------------------------------------------------------
 static void mapper_filter_usage(FILE* o, char* argv0, char* verb) {
-	fprintf(o, "Usage: %s %s [-v] {expression}\n", argv0, verb);
+	fprintf(o, "Usage: %s %s [-v] [-x] {expression}\n", argv0, verb);
 	fprintf(o, "Prints records for which {expression} evaluates to true.\n");
+	fprintf(o, "With -x, prints records for which {expression} evaluates to false.\n");
 	fprintf(o, "With -v, first prints the AST (abstract syntax tree) for the expression, which\n");
 	fprintf(o, "gives full transparency on the precedence and associativity rules of Miller's.\n");
 	fprintf(o, "grammar. Please use a dollar sign for field names and double-quotes for string\n");
@@ -47,9 +49,11 @@ static mapper_t* mapper_filter_parse_cli(int* pargi, int argc, char** argv) {
 	char* verb = argv[(*pargi)++];
 	char* mlr_dsl_expression = NULL;
 	int   print_asts = FALSE;
+	int   do_exclude = FALSE;
 
 	ap_state_t* pstate = ap_alloc();
 	ap_define_true_flag(pstate, "-v", &print_asts);
+	ap_define_true_flag(pstate, "-x", &do_exclude);
 
 	if (!ap_parse(pstate, verb, pargi, argc, argv)) {
 		mapper_filter_usage(stderr, argv[0], verb);
@@ -74,14 +78,15 @@ static mapper_t* mapper_filter_parse_cli(int* pargi, int argc, char** argv) {
 		mlr_dsl_ast_node_print(past->proot);
 	}
 
-	return mapper_filter_alloc(past->proot);
+	return mapper_filter_alloc(past->proot, do_exclude);
 }
 
 // ----------------------------------------------------------------
-static mapper_t* mapper_filter_alloc(mlr_dsl_ast_node_t* past) {
+static mapper_t* mapper_filter_alloc(mlr_dsl_ast_node_t* past, int do_exclude) {
 	mapper_filter_state_t* pstate = mlr_malloc_or_die(sizeof(mapper_filter_state_t));
 
 	pstate->pevaluator = lrec_evaluator_alloc_from_ast(past);
+	pstate->do_exclude = do_exclude;
 
 	mapper_t* pmapper = mlr_malloc_or_die(sizeof(mapper_t));
 
@@ -109,7 +114,7 @@ static sllv_t* mapper_filter_process(lrec_t* pinrec, context_t* pctx, void* pvst
 			return NULL;
 		} else {
 			mt_get_boolean_strict(&val);
-			if (val.u.boolv) {
+			if (val.u.boolv ^ pstate->do_exclude) {
 				return sllv_single(pinrec);
 			} else {
 				lrec_free(pinrec);
diff --git a/c/reg_test/expected/out b/c/reg_test/expected/out
index 573608710..f7ceff81f 100644
--- a/c/reg_test/expected/out
+++ b/c/reg_test/expected/out
@@ -3544,6 +3544,30 @@ a=wye,b=pan,i=5,x=0.5732889198020006,y=0.8636244699032729
 a=zee,b=pan,i=6,x=0.5271261600918548,y=0.49322128674835697
 a=eks,b=zee,i=7,x=0.6117840605678454,y=0.1878849191181694
 
+mlr filter -x $x>.3 ./reg_test/input/abixy
+a=wye,b=wye,i=3,x=0.20460330576630303,y=0.33831852551664776
+a=hat,b=wye,i=9,x=0.03144187646093577,y=0.7495507603507059
+
+mlr filter -x $x>0.3 ./reg_test/input/abixy
+a=wye,b=wye,i=3,x=0.20460330576630303,y=0.33831852551664776
+a=hat,b=wye,i=9,x=0.03144187646093577,y=0.7495507603507059
+
+mlr filter -x $x>0.3 && $y>0.3 ./reg_test/input/abixy
+a=wye,b=wye,i=3,x=0.20460330576630303,y=0.33831852551664776
+a=eks,b=wye,i=4,x=0.38139939387114097,y=0.13418874328430463
+a=eks,b=zee,i=7,x=0.6117840605678454,y=0.1878849191181694
+a=hat,b=wye,i=9,x=0.03144187646093577,y=0.7495507603507059
+
+mlr filter -x $x>0.3 || $y>0.3 ./reg_test/input/abixy
+
+mlr filter -x NR>=4 && NR <= 7 ./reg_test/input/abixy
+a=pan,b=pan,i=1,x=0.3467901443380824,y=0.7268028627434533
+a=eks,b=pan,i=2,x=0.7586799647899636,y=0.5221511083334797
+a=wye,b=wye,i=3,x=0.20460330576630303,y=0.33831852551664776
+a=zee,b=wye,i=8,x=0.5985540091064224,y=0.976181385699006
+a=hat,b=wye,i=9,x=0.03144187646093577,y=0.7495507603507059
+a=pan,b=wye,i=10,x=0.5026260055412137,y=0.9526183602969864
+
 mlr filter $nosuchfield>.3 ./reg_test/input/abixy
 
 mlr put $x2 = $x**2 ./reg_test/input/abixy
diff --git a/c/reg_test/run b/c/reg_test/run
index be1640d2d..f22436ab7 100755
--- a/c/reg_test/run
+++ b/c/reg_test/run
@@ -280,7 +280,12 @@ run_mlr filter '$x>0.3'   $indir/abixy
 run_mlr filter '$x>0.3 && $y>0.3'   $indir/abixy
 run_mlr filter '$x>0.3 || $y>0.3'   $indir/abixy
 run_mlr filter 'NR>=4 && NR <= 7'   $indir/abixy
-# xxx more ...
+
+run_mlr filter -x '$x>.3'    $indir/abixy
+run_mlr filter -x '$x>0.3'   $indir/abixy
+run_mlr filter -x '$x>0.3 && $y>0.3'   $indir/abixy
+run_mlr filter -x '$x>0.3 || $y>0.3'   $indir/abixy
+run_mlr filter -x 'NR>=4 && NR <= 7'   $indir/abixy
 
 run_mlr filter '$nosuchfield>.3'    $indir/abixy