diff --git a/contrib/oss-fuzz/build.sh b/contrib/oss-fuzz/build.sh
index 5cb5f66..6f5ae69 100755
--- a/contrib/oss-fuzz/build.sh
+++ b/contrib/oss-fuzz/build.sh
@@ -31,18 +31,15 @@
 > scripts/pnglibconf.dfa.temp
 mv scripts/pnglibconf.dfa.temp scripts/pnglibconf.dfa
 
-# build zlib library.
-(cd ../zlib; ./configure --zprefix; make -j$(nproc) clean; make -j$(nproc) all)
-
 # build the libpng library.
+cd ../libpng
 autoreconf -f -i
-CPPFLAGS="-I../zlib" LDFLAGS="-L../zlib" \
-  ./configure --with-zlib-prefix=z_ --with-libpng-prefix=OSS_FUZZ_
+./configure --with-libpng-prefix=OSS_FUZZ_
 make -j$(nproc) clean
 make -j$(nproc) libpng16.la
 
 # build libpng_read_fuzzer.
-$CXX $CXXFLAGS -std=c++11 -I. -I../zlib -L../zlib \
+$CXX $CXXFLAGS -std=c++11 -I. \
      $SRC/libpng/contrib/oss-fuzz/libpng_read_fuzzer.cc \
      -o $OUT/libpng_read_fuzzer \
      -lFuzzingEngine .libs/libpng16.a -lz