diff --git a/dnssec.go b/dnssec.go
index fd236e3a..3b1263c4 100644
--- a/dnssec.go
+++ b/dnssec.go
@@ -236,8 +236,7 @@ func isValidRRSet(rrset []RR) bool {
 // the values: Inception, Expiration, KeyTag, SignerName and Algorithm.
 // The rest is copied from the RRset. Sign returns true when the signing went OK,
 // otherwise false.
-// This function checks if RRSet is a proper (RFC 2181) RRSet, and returns
-// ErrRRSet if it is not.
+// There is no check if RRSet is a proper (RFC 2181) RRSet.
 // If OrigTTL is non zero, it is used as-is, otherwise the TTL of the RRset
 // is used as the OrigTTL.
 func (rr *RRSIG) Sign(k PrivateKey, rrset []RR) error {
@@ -249,10 +248,6 @@ func (rr *RRSIG) Sign(k PrivateKey, rrset []RR) error {
 		return ErrKey
 	}
 
-	if !isValidRRSet(rrset) {
-		return ErrRRset
-	}
-
 	rr.Hdr.Rrtype = TypeRRSIG
 	rr.Hdr.Name = rrset[0].Header().Name
 	rr.Hdr.Class = rrset[0].Header().Class
diff --git a/dnssec_test.go b/dnssec_test.go
index 26282432..e6c8384f 100644
--- a/dnssec_test.go
+++ b/dnssec_test.go
@@ -690,22 +690,22 @@ func TestInvalidRRSet(t *testing.T) {
 	badRecords[0] = &TXT{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
 	badRecords[1] = &TXT{Hdr: RR_Header{Name: "nama.cloudflare.com.", Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"_o/"}}
 
-	if err := signature.Sign(privatekey, badRecords); err != ErrRRset {
-		t.Fatal("Sign returned no error for record set with inconsistent names")
+	if isValidRRSet(badRecords) {
+		t.Fatal("Record set with inconsistent names considered valid")
 	}
 
 	badRecords[0] = &TXT{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
 	badRecords[1] = &A{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeA, Class: ClassINET, Ttl: 0}}
 
-	if err := signature.Sign(privatekey, badRecords); err != ErrRRset {
-		t.Fatal("Sign returned no error for record set with inconsistent record types")
+	if isValidRRSet(badRecords) {
+		t.Fatal("Record set with inconsistent record types considered valid")
 	}
 
 	badRecords[0] = &TXT{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
 	badRecords[1] = &TXT{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeTXT, Class: ClassCHAOS, Ttl: 0}, Txt: []string{"_o/"}}
 
-	if err := signature.Sign(privatekey, badRecords); err != ErrRRset {
-		t.Fatal("Sign returned no error for record set with inconsistent record class")
+	if isValidRRSet(badRecords) {
+		t.Fatal("Record set with inconsistent record class considered valid")
 	}
 
 	// Sign the good record set and then make sure verification fails on the bad record set