diff --git a/src/inferenceql/inference/gpm.cljc b/src/inferenceql/inference/gpm.cljc
index f61ca4c..6a3ee1b 100644
--- a/src/inferenceql/inference/gpm.cljc
+++ b/src/inferenceql/inference/gpm.cljc
@@ -12,6 +12,7 @@
             [inferenceql.inference.gpm.primitive-gpms.bernoulli :as bernoulli]
             [inferenceql.inference.gpm.primitive-gpms.categorical :as categorical]
             [inferenceql.inference.gpm.primitive-gpms.gaussian :as gaussian]
+            [inferenceql.inference.gpm.primitive-gpms.poisson :as poisson]
             [inferenceql.inference.gpm.proto :as gpm-proto]
             [inferenceql.inference.gpm.view :as view]))
 
@@ -152,6 +153,7 @@
    'inferenceql.inference.gpm.primitive_gpms.bernoulli.Bernoulli bernoulli/map->Bernoulli
    'inferenceql.inference.gpm.primitive_gpms.categorical.Categorical categorical/map->Categorical
    'inferenceql.inference.gpm.primitive_gpms.gaussian.Gaussian gaussian/map->Gaussian
+   'inferenceql.inference.gpm.primitive_gpms.poisson.Poisson poisson/map->Poisson
    'inferenceql.inference.gpm.view.View view/map->View})
 
 (defn as-gpm
diff --git a/test/inferenceql/inference/gpm/primitive_gpms/poisson_test.cljc b/test/inferenceql/inference/gpm/primitive_gpms/poisson_test.cljc
new file mode 100644
index 0000000..cb0b108
--- /dev/null
+++ b/test/inferenceql/inference/gpm/primitive_gpms/poisson_test.cljc
@@ -0,0 +1,22 @@
+(ns inferenceql.inference.gpm.primitive-gpms.poisson-test
+  (:require [clojure.math :as math]
+            [clojure.test :as test :refer [deftest is]]
+            [inferenceql.inference.gpm :as gpm]
+            [inferenceql.inference.gpm.primitive-gpms.poisson :as poisson]
+            [inferenceql.inference.gpm.proto :as gpm.proto]
+            [inferenceql.inference.utils :as utils]))
+
+(def var-name "poisson")
+
+(def poisson-pgpm
+  (let [suff-stats {:n 0 :sum-x 0 :sum-log-fact 0}
+        hypers {:a 2 :b 2}]
+    (poisson/spec->poisson var-name :suff-stats suff-stats :hyperparameters hypers)))
+
+(deftest logpdf
+  (let [targets {"poisson" 0}
+        constraints {"poisson" 1}]
+    (is (= 1.0 (math/exp (gpm.proto/logpdf poisson-pgpm {} {}))))
+    (is (= 1.0 (math/exp (gpm.proto/logpdf poisson-pgpm targets targets))))
+    (is (= ##-Inf (gpm.proto/logpdf poisson-pgpm targets constraints))))
+    (is (utils/almost-equal? -1.2163953243244932 (gpm.proto/logpdf poisson-pgpm {"poisson" 1} {}) utils/relerr 1E-8)))