diff --git a/Makefile b/Makefile
index 87705a4..77cd588 100644
--- a/Makefile
+++ b/Makefile
@@ -77,9 +77,9 @@ test: gen_data
 	psql q3c_test -c 'ANALYZE test_pm1'
 	psql q3c_test -c 'ANALYZE test_small'
 	mkdir -p results
-	cat sql/ang2ipix.sql | psql q3c_test > results/ang2ipix.out
+	cat sql/ang2ipix.sql | psql q3c_test > results/ang2ipix.out 2>&1
 	diff results/ang2ipix.out expected/ang2ipix.expected
-	cat sql/cone.sql | psql q3c_test > results/cone.out
+	cat sql/cone.sql | psql q3c_test > results/cone.out 2>&1
 	diff results/cone.out expected/cone.expected
 	cat sql/cone_join_rev.sql | psql q3c_test > results/cone.out
 	diff results/cone.out expected/cone.expected
@@ -99,7 +99,7 @@ test: gen_data
 	diff results/poly1.out expected/poly.expected
 	cat sql/version.sql | psql q3c_test > results/version.out
 	diff results/version.out expected/version.expected
-	cat sql/area.sql | psql q3c_test > results/area.out
+	cat sql/area.sql | psql q3c_test > results/area.out 2>&1
 	diff results/area.out expected/area.expected
 	dropdb q3c_test
 	createdb q3c_test
diff --git a/common.h b/common.h
index 844a227..2992142 100644
--- a/common.h
+++ b/common.h
@@ -46,6 +46,14 @@ typedef int64 q3c_ipix_t;
 #endif /* Q3C_IPIX_FMT */
 
 
+#ifndef Q3C_MAX_IPIX
+#define Q3C_MAX_IPIX ( (((q3c_ipix_t)1<<60)-1) + ((q3c_ipix_t)1<<60) + ((q3c_ipix_t)1<<62))
+/* This is maximum allowed ipix value 
+101 + 1111111111111....111
+         60 ones
+ */
+#endif /* Q3C_MAX_IPIX */
+
 
 /* If You have not specified the Q3C_LONG_DOUBLE macro then we will use simple
    double functions */
diff --git a/expected/ang2ipix.expected b/expected/ang2ipix.expected
index 02f0475..3290f79 100644
--- a/expected/ang2ipix.expected
+++ b/expected/ang2ipix.expected
@@ -118,3 +118,9 @@
  1000000
 (1 row)
 
+      q3c_ipix2ang      
+------------------------
+ {315,35.2643897079092}
+(1 row)
+
+ERROR:  Invalid ipix value
diff --git a/expected/area.expected b/expected/area.expected
index 3dfd737..f48b8a0 100644
--- a/expected/area.expected
+++ b/expected/area.expected
@@ -3,3 +3,7 @@
  t
 (1 row)
 
+ERROR:  Invalid depth. It should be less than 31.
+ERROR:  Invalid depth. It should be greater than 0.
+ERROR:  Invalid ipix value
+ERROR:  Invalid ipix value
diff --git a/q3c.c b/q3c.c
index 90e98df..ceaa6a7 100644
--- a/q3c.c
+++ b/q3c.c
@@ -274,7 +274,11 @@ Datum pgq3c_ipix2ang(PG_FUNCTION_ARGS)
 	char typalign;
 	ArrayType  *result;
 	ipix = PG_GETARG_INT64(0);
+	if ((ipix < 0) || (ipix > Q3C_MAX_IPIX))
+	  {
+		elog(ERROR, "Invalid ipix value");
 
+	  }
 	q3c_ipix2ang(&hprm, ipix, &ra, &dec);
 
 	data = ( Datum *) palloc(sizeof(Datum) * 2);
@@ -310,6 +314,14 @@ Datum pgq3c_pixarea(PG_FUNCTION_ARGS)
 	{
 		elog(ERROR, "Invalid depth. It should be less than 31.");
 	}
+	if (ipix < 0)
+	{
+		elog(ERROR, "Invalid ipix value");
+	}
+	if (ipix > Q3C_MAX_IPIX) 
+	{
+		elog(ERROR, "Invalid ipix value");
+	}
 
 	res = q3c_pixarea(&hprm, ipix, depth);
 
diff --git a/sql/ang2ipix.sql b/sql/ang2ipix.sql
index 26e9f90..c14da25 100644
--- a/sql/ang2ipix.sql
+++ b/sql/ang2ipix.sql
@@ -22,3 +22,5 @@ select q3c_dist_pm(0,0,3600000,0,0,0,90,0,90)<1e-9;
 select q3c_dist_pm(0,0,0,3600000,0,0,0,90,90)<1e-9;
 select sum((q3c_ang2ipix(((q3c_ipix2ang(q3c_ang2ipix(ra,dec)))[1]),(q3c_ipix2ang(q3c_ang2ipix(ra,dec)))[2])=q3c_ang2ipix(ra,dec))::int) from test;
 select sum((q3c_ang2ipix(ra::real,dec::real) = q3c_ang2ipix( (ra::real)::double precision, (dec::real)::double precision))::int) from test;
+select q3c_ipix2ang(0);
+select q3c_ipix2ang(-1);
diff --git a/sql/area.sql b/sql/area.sql
index de1ec1b..32a734b 100644
--- a/sql/area.sql
+++ b/sql/area.sql
@@ -1 +1,6 @@
 select 6*q3c_pixarea(0,30)/pi()/4. between 0.99999 and 1.00001;
+select q3c_pixarea(10,31);
+select q3c_pixarea(10,0);
+select q3c_pixarea(-1,4);
+select q3c_pixarea(6917529027641081856,4);
+