diff --git a/LICENSE-3rdparty.csv b/LICENSE-3rdparty.csv
index da9e709..ef9f891 100644
--- a/LICENSE-3rdparty.csv
+++ b/LICENSE-3rdparty.csv
@@ -1,5 +1,4 @@
 Component,Origin,License
-plugin,github.com/brianmario/yajl-ruby,MIT
 plugin,github.com/bundler/bundler,MIT
 plugin,github.com/ruby/openssl,BSD-2-Clause
 plugin,github.com/ruby/rake,MIT
\ No newline at end of file
diff --git a/fluent-plugin-datadog.gemspec b/fluent-plugin-datadog.gemspec
index 9acb04d..1ab8110 100644
--- a/fluent-plugin-datadog.gemspec
+++ b/fluent-plugin-datadog.gemspec
@@ -29,7 +29,6 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "bundler", "~> 2.1"
   spec.add_development_dependency "test-unit", '~> 3.1'
   spec.add_development_dependency "rake", "~> 12.0"
-  spec.add_development_dependency "yajl-ruby", "~> 1.2"
   spec.add_development_dependency 'webmock', "~> 3.6.0"
 
   spec.metadata      = {
diff --git a/lib/fluent/plugin/out_datadog.rb b/lib/fluent/plugin/out_datadog.rb
index 23c30f0..e316ccb 100644
--- a/lib/fluent/plugin/out_datadog.rb
+++ b/lib/fluent/plugin/out_datadog.rb
@@ -5,7 +5,7 @@
 
 require "socket"
 require "openssl"
-require "yajl"
+require "json"
 require "zlib"
 require "fluent/plugin/output"
 
@@ -118,10 +118,10 @@ def format(tag, time, record)
     # is compatible with Time.at below.
     record = enrich_record(tag, time.to_f, record)
     if @use_http
-      record = Yajl.dump(record)
+      record = JSON.generate(record)
     else
       if @use_json
-        record = "#{api_key} #{Yajl.dump(record)}"
+        record = "#{api_key} #{JSON.generate(record)}"
       else
         record = "#{api_key} #{record}"
       end