diff --git a/setup.py b/setup.py
index 3cf26d1e..a9960a82 100644
--- a/setup.py
+++ b/setup.py
@@ -122,6 +122,10 @@
     # Note that this is a string of words separated by whitespace, not a list.
     keywords='sample setuptools development',  # Optional
 
+    # When your source code is in a subdirectory under the project root, e.g.
+    # `src/`, it is necessary to specify the `package_dir` argument.
+    package_dir={'': 'src'},  # Optional
+
     # You can just specify package directories manually here if your project is
     # simple. Or you can use find_packages().
     #
@@ -131,7 +135,7 @@
     #
     #   py_modules=["my_module"],
     #
-    packages=find_packages(exclude=['contrib', 'docs', 'tests']),  # Required
+    packages=find_packages(where='src'),  # Required
 
     # Specify which Python versions you support. In contrast to the
     # 'Programming Language' classifiers above, 'pip install' will check this
diff --git a/sample/__init__.py b/src/sample/__init__.py
similarity index 100%
rename from sample/__init__.py
rename to src/sample/__init__.py
diff --git a/sample/package_data.dat b/src/sample/package_data.dat
similarity index 100%
rename from sample/package_data.dat
rename to src/sample/package_data.dat