diff --git a/poetry/packages/__init__.py b/poetry/packages/__init__.py
index e0a2203c9d3..a829858deb2 100644
--- a/poetry/packages/__init__.py
+++ b/poetry/packages/__init__.py
@@ -33,8 +33,8 @@ def dependency_from_pep_508(name):
     name = parts[0].strip()
     if len(parts) > 1:
         rest = parts[1]
-        if ";" in rest:
-            name += ";" + rest.split(";", 1)[1]
+        if " ;" in rest:
+            name += " ;" + rest.split(" ;", 1)[1]
 
     req = Requirement(name)
 
diff --git a/poetry/utils/helpers.py b/poetry/utils/helpers.py
index 3ecef0c391e..85d18a71d44 100644
--- a/poetry/utils/helpers.py
+++ b/poetry/utils/helpers.py
@@ -83,7 +83,7 @@ def parse_requires(requires):  # type: (str) -> List[str]
             continue
 
         if current_marker:
-            line = "{}; {}".format(line, current_marker)
+            line = "{} ; {}".format(line, current_marker)
 
         requires_dist.append(line)
 
diff --git a/tests/packages/test_main.py b/tests/packages/test_main.py
index 586be5a31b8..5559057e4e9 100644
--- a/tests/packages/test_main.py
+++ b/tests/packages/test_main.py
@@ -183,6 +183,22 @@ def test_dependency_from_pep_508_with_git_url():
     assert "1.2" == dep.reference
 
 
+def test_dependency_from_pep_508_with_git_url_and_comment_and_extra():
+    name = (
+        "poetry @ git+https://github.com/python-poetry/poetry.git@b;ar;#egg=poetry"
+        ' ; extra == "foo;"'
+    )
+
+    dep = dependency_from_pep_508(name)
+
+    assert "poetry" == dep.name
+    assert dep.is_vcs()
+    assert "git" == dep.vcs
+    assert "https://github.com/python-poetry/poetry.git" == dep.source
+    assert "b;ar;" == dep.reference
+    assert dep.in_extras == ["foo;"]
+
+
 def test_dependency_from_pep_508_with_url():
     name = "django-utils @ https://example.com/django-utils-1.0.0.tar.gz"
 
diff --git a/tests/utils/test_helpers.py b/tests/utils/test_helpers.py
index d34061c88d6..eb7ce191f18 100644
--- a/tests/utils/test_helpers.py
+++ b/tests/utils/test_helpers.py
@@ -29,6 +29,9 @@ def test_parse_requires():
 
 [:python_version >= "3.4.0.0" and python_version < "3.6.0.0"]
 zipfile36>=0.1.0.0,<0.2.0.0
+
+[dev]
+isort@ git+git://github.com/timothycrosley/isort.git@e63ae06ec7d70b06df9e528357650281a3d3ec22#egg=isort
 """
     result = parse_requires(requires)
     expected = [
@@ -45,10 +48,11 @@ def test_parse_requires():
         "msgpack-python>=0.5.0.0,<0.6.0.0",
         "pyparsing>=2.2.0.0,<3.0.0.0",
         "requests-toolbelt>=0.8.0.0,<0.9.0.0",
-        'typing>=3.6.0.0,<4.0.0.0; (python_version >= "2.7.0.0" and python_version < "2.8.0.0") or (python_version >= "3.4.0.0" and python_version < "3.5.0.0")',
-        'virtualenv>=15.2.0.0,<16.0.0.0; python_version >= "2.7.0.0" and python_version < "2.8.0.0"',
-        'pathlib2>=2.3.0.0,<3.0.0.0; python_version >= "2.7.0.0" and python_version < "2.8.0.0"',
-        'zipfile36>=0.1.0.0,<0.2.0.0; python_version >= "3.4.0.0" and python_version < "3.6.0.0"',
+        'typing>=3.6.0.0,<4.0.0.0 ; (python_version >= "2.7.0.0" and python_version < "2.8.0.0") or (python_version >= "3.4.0.0" and python_version < "3.5.0.0")',
+        'virtualenv>=15.2.0.0,<16.0.0.0 ; python_version >= "2.7.0.0" and python_version < "2.8.0.0"',
+        'pathlib2>=2.3.0.0,<3.0.0.0 ; python_version >= "2.7.0.0" and python_version < "2.8.0.0"',
+        'zipfile36>=0.1.0.0,<0.2.0.0 ; python_version >= "3.4.0.0" and python_version < "3.6.0.0"',
+        'isort@ git+git://github.com/timothycrosley/isort.git@e63ae06ec7d70b06df9e528357650281a3d3ec22#egg=isort ; extra == "dev"',
     ]
     assert result == expected