diff --git a/skeletons/BIT_STRING_oer.c b/skeletons/BIT_STRING_oer.c
new file mode 100644
index 0000000..55cee4a
--- /dev/null
+++ b/skeletons/BIT_STRING_oer.c
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2017 Lev Walkin <vlm@lionet.info>.
+ * All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef ASN_DISABLE_OER_SUPPORT
+
+#include <asn_internal.h>
+#include <BIT_STRING.h>
+#include <errno.h>
+
+asn_dec_rval_t
+BIT_STRING_decode_oer(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td,
+                      const asn_oer_constraints_t *constraints, void **sptr,
+                      const void *ptr, size_t size) {
+    BIT_STRING_t *st = (BIT_STRING_t *)*sptr;
+    const asn_oer_constraints_t *cts =
+        constraints ? constraints : td->oer_constraints;
+    ssize_t ct_size = cts ? cts->size : -1;
+    asn_dec_rval_t rval = {RC_OK, 0};
+    size_t expected_length = 0;
+
+    (void)opt_codec_ctx;
+
+    if(!st) {
+        st = (BIT_STRING_t *)(*sptr = CALLOC(1, sizeof(*st)));
+        if(!st) ASN__DECODE_FAILED;
+    }
+
+    if(ct_size >= 0) {
+        expected_length = (ct_size + 7) >> 3;
+        st->bits_unused = (8 - (ct_size & 7)) & 7;
+    } else {
+        /*
+         * X.696 (08/2015) #13.3.1
+         * Encode length determinant as _number of octets_, but only
+         * if upper bound is not equal to lower bound.
+         */
+        ssize_t len_len = oer_fetch_length(ptr, size, &expected_length);
+        if(len_len > 0) {
+            ptr = (const char *)ptr + len_len;
+            size -= len_len;
+        } else if(len_len == 0) {
+            ASN__DECODE_STARVED;
+        } else if(len_len < 0) {
+            ASN__DECODE_FAILED;
+        }
+
+        if(expected_length < 1) {
+            ASN__DECODE_STARVED;
+        }
+
+        st->bits_unused = ((const uint8_t *)ptr)[0];
+        if(st->bits_unused & ~7) {
+            ASN_DEBUG("%s: unused bits outside of 0..7 range", td->name);
+            ASN__DECODE_FAILED;
+        }
+        ptr = (const char *)ptr + 1;
+        size--;
+        expected_length--;
+        rval.consumed = len_len + 1;
+    }
+
+    if(size < expected_length) {
+        ASN__DECODE_STARVED;
+    } else {
+        uint8_t *buf = MALLOC(expected_length + 1);
+        if(buf == NULL) {
+            ASN__DECODE_FAILED;
+        } else {
+            memcpy(buf, ptr, expected_length);
+            buf[expected_length] = '\0';
+        }
+        FREEMEM(st->buf);
+        st->buf = buf;
+        st->size = expected_length;
+        if(expected_length > 0) {
+            buf[expected_length - 1] &= (0xff << st->bits_unused);
+        }
+
+        rval.consumed += expected_length;
+        return rval;
+    }
+}
+
+/*
+ * Encode as Canonical OER.
+ */
+asn_enc_rval_t
+BIT_STRING_encode_oer(asn_TYPE_descriptor_t *td,
+                        const asn_oer_constraints_t *constraints, void *sptr,
+                        asn_app_consume_bytes_f *cb, void *app_key) {
+    asn_enc_rval_t er = {-1,td,sptr};
+    (void)constraints;
+    (void)cb;
+    (void)app_key;
+    return er;
+}
+
+
+#endif  /* ASN_DISABLE_OER_SUPPORT */