diff --git a/.travis.yml b/.travis.yml
index 432216fb3a..f544cdd945 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -30,6 +30,7 @@ env:
   - FLOATX='float64' TESTCMD="--durations=10 --cov-append pymc3/tests/test_distributions_random.py pymc3/tests/test_shared.py pymc3/tests/test_smc.py pymc3/tests/test_sampling.py pymc3/tests/test_parallel_sampling.py pymc3/tests/test_dist_math.py pymc3/tests/test_distribution_defaults.py pymc3/tests/test_distributions_timeseries.py pymc3/tests/test_random.py"
   - FLOATX='float64' TESTCMD="--durations=10 --cov-append pymc3/tests/test_examples.py pymc3/tests/test_posteriors.py pymc3/tests/test_gp.py"
   - FLOATX='float64' TESTCMD="--durations=10 --cov-append pymc3/tests/test_variational_inference.py pymc3/tests/test_updates.py pymc3/tests/test_shape_handling.py"
+  - PYTHON_VERSION=3.5 FLOATX='float64' ENVNAME="py35_testenv" TESTCMD="--cov-append pymc3/tests/test_sampling.py pymc3/tests/test_model_graph.py"
 
 script:
   - . ./scripts/test.sh $TESTCMD
diff --git a/RELEASE-NOTES.md b/RELEASE-NOTES.md
index 1fe060bef1..51f2376f7d 100644
--- a/RELEASE-NOTES.md
+++ b/RELEASE-NOTES.md
@@ -45,6 +45,7 @@
 - Fixed an issue in `model_graph` that caused construction of the graph of the model for rendering to hang: replaced a search over the powerset of the nodes with a breadth-first search over the nodes. Fix for #3458.
 - Removed variable annotations from `model_graph` but left type hints (Fix for #3465). This means that we support `python>=3.5.4`.
 - Default `target_accept`for `HamiltonianMC` is now 0.65, as suggested in Beskos et. al. 2010 and Neal 2001.
+- Fixed bug in `draw_values` that lead to intermittent errors in python3.5. This happened with some deterministic nodes that were drawn but not added to `givens`.
 
 ### Deprecations
 
diff --git a/pymc3/distributions/distribution.py b/pymc3/distributions/distribution.py
index 0164ff691d..b455480e36 100644
--- a/pymc3/distributions/distribution.py
+++ b/pymc3/distributions/distribution.py
@@ -401,8 +401,7 @@ def draw_values(params, point=None, size=None):
                     # nodes in the `params` list.
                     stack.extend([node for node in named_nodes_parents[next_]
                                   if node is not None and
-                                  (node, size) not in drawn and
-                                  node not in params])
+                                  (node, size) not in drawn])
 
         # the below makes sure the graph is evaluated in order
         # test_distributions_random::TestDrawValues::test_draw_order fails without it
@@ -420,6 +419,20 @@ def draw_values(params, point=None, size=None):
                     evaluated[param_idx] = drawn[(param, size)]
                 else:
                     try:  # might evaluate in a bad order,
+                        # Sometimes _draw_value recurrently calls draw_values.
+                        # This may set values for certain nodes in the drawn
+                        # dictionary, but they don't get added to the givens
+                        # dictionary. Here, we try to fix that.
+                        if param in named_nodes_children:
+                            for node in named_nodes_children[param]:
+                                if (
+                                    node.name not in givens and
+                                    (node, size) in drawn
+                                ):
+                                    givens[node.name] = (
+                                        node,
+                                        drawn[(node, size)]
+                                    )
                         value = _draw_value(param,
                                             point=point,
                                             givens=givens.values(),
diff --git a/scripts/create_testenv.sh b/scripts/create_testenv.sh
index 7604fc330e..8970f0e675 100755
--- a/scripts/create_testenv.sh
+++ b/scripts/create_testenv.sh
@@ -20,7 +20,7 @@ command -v conda >/dev/null 2>&1 || {
   exit 1;
 }
 
-ENVNAME="testenv"
+ENVNAME="${ENVNAME:-testenv}" # if no ENVNAME is specified, use testenv
 PYTHON_VERSION=${PYTHON_VERSION:-3.6} # if no python specified, use 3.6
 
 if [ -z ${GLOBAL} ]
@@ -33,10 +33,11 @@ then
     fi
     source activate ${ENVNAME}
 fi
-conda install --yes numpy scipy mkl-service
+pip install --upgrade pip
+
+conda install --yes mkl-service
 conda install --yes -c conda-forge python-graphviz
 
-pip install --upgrade pip
 
 #  Install editable using the setup.py
 
diff --git a/scripts/install_miniconda.sh b/scripts/install_miniconda.sh
index 6db6f64934..b4035f4528 100755
--- a/scripts/install_miniconda.sh
+++ b/scripts/install_miniconda.sh
@@ -46,3 +46,5 @@ fi
 export PATH="$INSTALL_FOLDER/bin:$PATH"
 echo "Adding $INSTALL_FOLDER to PATH.  Consider adding it in your .rc file as well."
 conda update -q -y conda
+# Uninstalling miniconda's numpy to avoid conflicting versions when creating the test env
+pip uninstall -y numpy
diff --git a/setup.py b/setup.py
index f6bb2b2e38..014b9e39ea 100755
--- a/setup.py
+++ b/setup.py
@@ -59,6 +59,7 @@ def get_version():
           package_data={'docs': ['*']},
           include_package_data=True,
           classifiers=classifiers,
+          python_requires=">=3.5.4",
           install_requires=install_reqs,
           extras_require={
               "plots": ["arviz"],