diff --git a/lib/prometheus/client/metric.rb b/lib/prometheus/client/metric.rb
index 1bb43347..83b35204 100644
--- a/lib/prometheus/client/metric.rb
+++ b/lib/prometheus/client/metric.rb
@@ -85,6 +85,7 @@ def validate_docstring(docstring)
       def label_set_for(labels)
         # We've already validated, and there's nothing to merge. Save some cycles
         return preset_labels if @all_labels_preset && labels.empty?
+        labels = labels.map { |k,v| [k, v.to_s] }.to_h
         @validator.validate_labelset!(preset_labels.merge(labels))
       end
     end
diff --git a/spec/examples/metric_example.rb b/spec/examples/metric_example.rb
index ced2c317..4dca8c64 100644
--- a/spec/examples/metric_example.rb
+++ b/spec/examples/metric_example.rb
@@ -63,5 +63,17 @@
         expect(subject.get(labels: { test: 'label' })).to be_a(type)
       end
     end
+
+    context "with non-string label values" do
+      subject { described_class.new(:foo, docstring: 'Labels', labels: [:test]) }
+
+      it "converts labels to strings for consistent storage" do
+        incrementor.call(test: :label)
+        expect(subject.get(labels: { test: 'label' })).to eq(1.0)
+      end
+
+      context "and all labels preset" do
+      end
+    end
   end
 end
diff --git a/spec/prometheus/client/counter_spec.rb b/spec/prometheus/client/counter_spec.rb
index 806c55b6..c3fee3d1 100644
--- a/spec/prometheus/client/counter_spec.rb
+++ b/spec/prometheus/client/counter_spec.rb
@@ -20,6 +20,7 @@
 
   it_behaves_like Prometheus::Client::Metric do
     let(:type) { Float }
+    let(:incrementor) { ->(labels) { subject.increment(labels: labels); pp subject}  }
   end
 
   describe '#increment' do