diff --git a/graphql/types.lua b/graphql/types.lua
index 77db320..3cd7a0f 100644
--- a/graphql/types.lua
+++ b/graphql/types.lua
@@ -286,11 +286,7 @@ local function isLong(value)
   end
 
   if type(value) == 'cdata' then
-    if ffi.istype('int64_t', value) then
-      return true
-    elseif ffi.istype('uint64_t', value) then
-      return value < 2^63
-    end
+    return ffi.istype('int64_t', value) or ffi.istype('uint64_t', value)
   end
 
   return false
@@ -299,9 +295,7 @@ end
 local function coerceLong(value)
   if value ~= nil then
     value = tonumber64(value)
-    if not isLong(value) then return end
   end
-
   return value
 end
 
diff --git a/test/integration/graphql_test.lua b/test/integration/graphql_test.lua
index 6462450..d67056b 100644
--- a/test/integration/graphql_test.lua
+++ b/test/integration/graphql_test.lua
@@ -96,7 +96,7 @@ function g.test_variables()
     local function callback(_, args)
         local result = ''
         for _, tuple in ipairs(getmetatable(args).__index) do
-            result = result .. tuple.value
+            result = result .. tostring(tuple.value)
         end
         return result
     end
@@ -184,10 +184,10 @@ function g.test_variables()
     )
 
     t.assert_error_msg_equals(
-            'Could not coerce value "18446744073709551614" to type "Long"',
+            'Could not coerce value "18446744073709551617" to type "Long"',
             function()
                 check_request([[
-                    query { test(arg: "", arg4: 18446744073709551614) }
+                    query { test(arg: "", arg4: 18446744073709551617) }
                 ]], query_schema)
             end
     )
@@ -2147,3 +2147,37 @@ function g.test_non_finite_float()
             query_schema, nil, nil, {variables = variables})
     end
 end
+
+function g.test_huge_cdata_number()
+     local query = [[
+        query ($x: Long!) { test(arg: $x) }
+    ]]
+
+    local function callback(_, args)
+        return args[1].value
+    end
+
+    local query_schema = {
+        ['test'] = {
+            kind = types.long.nonNull,
+            arguments = {
+                arg = types.long.nonNull,
+            },
+            resolve = callback,
+        }
+    }
+
+    local test_values = {
+        {4503599627370495ULL, "{\"test\":4503599627370495}"},
+        {9223372036854775807ULL, "{\"test\":9223372036854775807}"},
+        {-1LL, "{\"test\":-1}"},
+        {-1ULL, "{\"test\":18446744073709551615}"}}
+
+    for _, v in ipairs(test_values) do
+        local variables = {x = v[1]}
+        local res = check_request(query, query_schema, nil, nil, {variables = variables})
+        t.assert_type(res, 'table')
+        t.assert_equals(res.test, v[1])
+        t.assert_equals(json.encode(res), v[2])
+    end
+end