diff --git a/lib/toApiFormat.js b/lib/toApiFormat.js
index c9799d0..4f9ba39 100644
--- a/lib/toApiFormat.js
+++ b/lib/toApiFormat.js
@@ -1,42 +1,59 @@
 'use strict';
-var _ = require('lodash');
+var _ = require('lodash')
+  , pointer = require('json-pointer');
+
+var excludeList = [
+  '/substitution_data',
+  '/tags',
+  '/metadata',
+  '/attributes',
+  '/headers',
+  '/content/email_rfc822'
+];
+
+function snakedKeyClone(source) {
+
+  if (!_.isObject(source)) {
+    return source;
+  }
+
+  var target = {};
+
+  if (Array.isArray(source)) {
+    target = [];
+    for (var i = 0; i < source.length; i++) {
+      target.push(snakedKeyClone(source[i]));
+    }
+    return target;
+  }
+
+  Object.keys(source).forEach(function(key) {
+    target[_.snakeCase(key)] = snakedKeyClone(source[key]);
+  });
+
+  return target;
+}
 
 module.exports = function toApiFormat(source) {
 
-  var dest = {};
-  // List of property names which we do not want to modify the sub-property names
-  var excludeList = ['substitution_data', 'tags', 'metadata', 'attributes', 'headers'];
-
-  try{
-    // Handle arrays (Only need to handle arrays of objects for our use case.)
-    if(Array.isArray(source) && _.isPlainObject(source[0])) {
-      dest = [];
-      for(var i = 0; i < source.length; i++) {
-        dest.push(toApiFormat(source[i]));
-      }
-      return dest;
+  var excludedObjects = {};
+
+  // Look in the source object for the excluded pointers and take a copy of the
+  // objects pointed to by those keys. Then remove them from the source object.
+  excludeList.forEach(function(exclusionPointer) {
+    if (pointer.has(source, exclusionPointer)) {
+      pointer.set(excludedObjects, exclusionPointer, pointer.get(source, exclusionPointer));
+      pointer.remove(source, exclusionPointer);
     }
+  });
 
-    // Handle objects
-    Object.keys(source).forEach(function(key) {
-
-      // Cache snake_cased keys
-      var snakedKey = _.snakeCase(key);
-
-      // Exclude appropriately
-      if( -1 === excludeList.indexOf(key)) {
-        dest[snakedKey] = source[key];
-        if( _.isObject (source[key] ) ) {
-          dest[snakedKey] = toApiFormat(source[key]);
-        }
-      } else {
-        dest[snakedKey] = source[key];
-      }
-    });
-  } catch(e) {
-    // Errors
-    return e;
-  }
-  // No errors return results
-  return dest;
+  // Make a clone of the remaining source object but with snaked case keys
+  var target = snakedKeyClone(source);
+
+  // Reinstated the un-modified objects into the target
+  pointer.walk(excludedObjects, function(val, ptr) {
+    pointer.set(target, ptr, val);
+  });
+
+  return target;
 };
diff --git a/package.json b/package.json
index 9e8a30e..5461d3a 100644
--- a/package.json
+++ b/package.json
@@ -40,6 +40,7 @@
     "xunit-file": "0.0.5"
   },
   "dependencies": {
+    "json-pointer": "^0.5.0",
     "lodash": "^3.9.3",
     "request": "2.42.0"
   }
diff --git a/test/spec/toApiFormat.spec.js b/test/spec/toApiFormat.spec.js
index a0a3ca6..0cd1b4f 100644
--- a/test/spec/toApiFormat.spec.js
+++ b/test/spec/toApiFormat.spec.js
@@ -24,6 +24,9 @@ describe('toApiFormat', function() {
         {name: 'John Doe', address: 'j.doe@sparkpost.com'}
         , {name: 'Sam Jones', address: 's.jones@sparkpost.com'}
       ]
+      , content: {
+        email_rfc822: 'a message'
+      }
       , fizzArr: [
         {
           buzzInga: "buzz"
@@ -53,6 +56,9 @@ describe('toApiFormat', function() {
         {name: 'John Doe', address: 'j.doe@sparkpost.com'}
         , {name: 'Sam Jones', address: 's.jones@sparkpost.com'}
       ]
+      , content: {
+        email_rfc822: 'a message'
+      }
       , fizz_arr: [
         {
           buzz_inga: "buzz"
diff --git a/test/spec/transmissions.spec.js b/test/spec/transmissions.spec.js
index 712d8c7..bbe50e3 100644
--- a/test/spec/transmissions.spec.js
+++ b/test/spec/transmissions.spec.js
@@ -108,5 +108,20 @@ describe('Transmissions Library', function() {
         done();
       });
     });
+
+    it('should leave email_rfc822 content keys intact', function(done) {
+      var options = {
+        transmissionBody: {
+          content: {
+            email_rfc822: 'Content-Type: text/plain\nFrom: From Envelope <from@example.com>\nSubject: Example Email\n\nHello World'
+          }
+        }
+      };
+
+      transmission.send(options, function(err, data) {
+        expect(client.post.firstCall.args[0].json.content).to.have.property('email_rfc822');
+        done();
+      });
+    });
   });
 });