diff --git a/README.md b/README.md
index f68cdfb..ed138c9 100644
--- a/README.md
+++ b/README.md
@@ -37,6 +37,9 @@ var result = percentile(
 console.log(result); // 8
 
 ```
+## Notes
+
+Non-numeric (NaN) values are treated as the smallest values, Eg `percentile(50, [ 5, 2, NaN]) === 2`
 
 ## Author
 
diff --git a/lib/index.js b/lib/index.js
index a283f9f..dce505d 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -61,6 +61,9 @@ function percentile(p, list, fn) {
       b = fn(b);
     }
 
+    a = Number.isNaN(a) ? Number.NEGATIVE_INFINITY : a;
+    b = Number.isNaN(b) ? Number.NEGATIVE_INFINITY : b;
+    
     if (a > b) return 1;
     if (a < b) return -1;
 
diff --git a/test/index.js b/test/index.js
index f19fdf2..de471f1 100644
--- a/test/index.js
+++ b/test/index.js
@@ -24,6 +24,8 @@ const stubsSimple = [
   { percentile: 75, list: shuffleArray(generateArraySimple(100)), result: 75 },
   { percentile: 100, list: shuffleArray(generateArraySimple(100)), result: 100 },
 
+  { percentile: 75, list: [NaN, NaN, 1, 100], result: 1 },
+  { percentile: 75, list: [1, 100, NaN, NaN], result: 1 },
   { percentile: 75, list: shuffleArray([].concat(generateArraySimple(100), generateArraySimple(30))), result: 68 }
 ];