diff --git a/src/sc_containers.c b/src/sc_containers.c
index 47c86d7..b9a1979 100644
--- a/src/sc_containers.c
+++ b/src/sc_containers.c
@@ -23,7 +23,7 @@
 
 #include <sc_containers.h>
 #ifdef SC_HAVE_ZLIB
-#include <zlib.h>
+#include <zlib-ng.h>
 #endif
 
 /* array routines */
@@ -636,13 +636,13 @@ sc_array_checksum (sc_array_t * array)
   unsigned int        crc;
   size_t              bytes;
 
-  crc = adler32 (0, Z_NULL, 0);
+  crc = zng_adler32 (0, Z_NULL, 0);
   if (array->elem_count == 0) {
     return crc;
   }
 
   bytes = array->elem_count * array->elem_size;
-  crc = adler32 (crc, (const Bytef *) array->array, bytes);
+  crc = zng_adler32 (crc, (const Bytef *) array->array, bytes);
 
   return crc;
 #else
diff --git a/src/sc_io.c b/src/sc_io.c
index a7ed413..bc2df7d 100644
--- a/src/sc_io.c
+++ b/src/sc_io.c
@@ -25,7 +25,7 @@
 #include <sc_puff.h>
 #include <libb64.h>
 #ifdef SC_HAVE_ZLIB
-#include <zlib.h>
+#include <zlib-ng.h>
 #endif
 
 #ifndef SC_ENABLE_MPIIO
@@ -706,7 +706,7 @@ sc_io_encode_zlib (sc_array_t *data, sc_array_t *out,
 #ifndef SC_HAVE_ZLIB
   input_compress_bound = sc_io_noncompress_bound (input_size);
 #else
-  input_compress_bound = compressBound ((uLong) input_size);
+  input_compress_bound = zng_compressBound ((uLong) input_size);
 #endif /* SC_HAVE_ZLIB */
   sc_array_init_count (&compressed, 1,
                        SC_IO_ENCODE_INFO_LEN + input_compress_bound);
@@ -715,9 +715,9 @@ sc_io_encode_zlib (sc_array_t *data, sc_array_t *out,
   sc_io_noncompress (compressed.array + SC_IO_ENCODE_INFO_LEN,
                      input_compress_bound, data->array, input_size);
 #else
-  zrv = compress2 ((Bytef *) compressed.array + SC_IO_ENCODE_INFO_LEN,
-                   &input_compress_bound, (Bytef *) data->array,
-                   (uLong) input_size, zlib_compression_level);
+  zrv = zng_compress2 ((Bytef *) compressed.array + SC_IO_ENCODE_INFO_LEN,
+                       &input_compress_bound, (Bytef *) data->array,
+                       (uLong) input_size, zlib_compression_level);
   SC_CHECK_ABORT (zrv == Z_OK, "Error on zlib compression");
 #endif /* SC_HAVE_ZLIB */
 
@@ -993,9 +993,9 @@ sc_io_decode (sc_array_t *data, sc_array_t *out,
   }
 #else
   uncompsize = (uLong) encoded_size;
-  zrv = uncompress ((Bytef *) out->array, &uncompsize,
-                    (Bytef *) (compressed.array + SC_IO_ENCODE_INFO_LEN),
-                    ocnt - SC_IO_ENCODE_INFO_LEN);
+  zrv = zng_uncompress ((Bytef *) out->array, &uncompsize,
+                        (Bytef *) (compressed.array + SC_IO_ENCODE_INFO_LEN),
+                        ocnt - SC_IO_ENCODE_INFO_LEN);
   if (zrv != Z_OK) {
     SC_LERROR ("zlib uncompress error\n");
     goto decode_error;
@@ -1120,9 +1120,9 @@ sc_vtk_write_compressed (FILE * vtkfile, char *numeric_data,
   base64_init_encodestate (&encode_state);
   for (theblock = 0; theblock < numregularblocks; ++theblock) {
     comp_length = code_length;
-    retval = compress2 ((Bytef *) comp_data, &comp_length,
-                        (const Bytef *) (numeric_data + theblock * blocksize),
-                        (uLong) blocksize, Z_BEST_COMPRESSION);
+    retval = zng_compress2 ((Bytef *) comp_data, &comp_length,
+                            (const Bytef *) (numeric_data + theblock * blocksize),
+                            (uLong) blocksize, Z_BEST_COMPRESSION);
     SC_CHECK_ZLIB (retval);
     compression_header[3 + theblock] = comp_length;
     base_length = base64_encode_block (comp_data, comp_length,
@@ -1135,9 +1135,9 @@ sc_vtk_write_compressed (FILE * vtkfile, char *numeric_data,
   /* write odd-sized last block if necessary */
   if (lastsize > 0) {
     comp_length = code_length;
-    retval = compress2 ((Bytef *) comp_data, &comp_length,
-                        (const Bytef *) (numeric_data + theblock * blocksize),
-                        (uLong) lastsize, Z_BEST_COMPRESSION);
+    retval = zng_compress2 ((Bytef *) comp_data, &comp_length,
+                            (const Bytef *) (numeric_data + theblock * blocksize),
+                            (uLong) lastsize, Z_BEST_COMPRESSION);
     SC_CHECK_ZLIB (retval);
     compression_header[3 + theblock] = comp_length;
     base_length = base64_encode_block (comp_data, comp_length,
diff --git a/test/test_builtin.c b/test/test_builtin.c
index 371aff6..9a99c2d 100644
--- a/test/test_builtin.c
+++ b/test/test_builtin.c
@@ -27,7 +27,7 @@
 
 /* truthfully, the libraries below are not builtin anymore */
 #ifdef SC_HAVE_ZLIB
-#include <zlib.h>
+#include <zlib-ng.h>
 #endif
 
 static int
@@ -87,13 +87,13 @@ test_zlib (void)
   char                b3[BUFSIZ];
   uLong               adler0, adler1, adler2, adler3a, adler3b;
 
-  adler0 = adler32 (0L, Z_NULL, 0);
-  adler1 = adler32 (adler0, (const Bytef *) b1, l1);
-  adler2 = adler32 (adler0, (const Bytef *) b2, l2);
-  adler3a = adler32_combine (adler1, adler2, l2);
+  adler0 = zng_adler32 (0L, Z_NULL, 0);
+  adler1 = zng_adler32 (adler0, (const Bytef *) b1, l1);
+  adler2 = zng_adler32 (adler0, (const Bytef *) b2, l2);
+  adler3a = zng_adler32_combine (adler1, adler2, l2);
 
   snprintf (b3, BUFSIZ, "%s%s", b1, b2);
-  adler3b = adler32 (adler0, (const Bytef *) b3, l1 + l2);
+  adler3b = zng_adler32 (adler0, (const Bytef *) b3, l1 + l2);
 
   return adler3a != adler3b;
 }