diff --git a/NzbDrone.Api/NzbDrone.Api.csproj b/NzbDrone.Api/NzbDrone.Api.csproj
index e3110a089..f2bb6115f 100644
--- a/NzbDrone.Api/NzbDrone.Api.csproj
+++ b/NzbDrone.Api/NzbDrone.Api.csproj
@@ -59,8 +59,9 @@
       <SpecificVersion>False</SpecificVersion>
       <HintPath>..\packages\AutoMapper.2.2.1\lib\net40\AutoMapper.dll</HintPath>
     </Reference>
-    <Reference Include="FluentValidation">
-      <HintPath>..\packages\FluentValidation.3.4.6.0\lib\Net40\FluentValidation.dll</HintPath>
+    <Reference Include="FluentValidation, Version=4.0.0.0, Culture=neutral, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
+      <HintPath>..\packages\FluentValidation.4.0.0.0\lib\Net40\FluentValidation.dll</HintPath>
     </Reference>
     <Reference Include="Nancy, Version=0.16.1.0, Culture=neutral, processorArchitecture=MSIL">
       <SpecificVersion>False</SpecificVersion>
diff --git a/NzbDrone.Api/packages.config b/NzbDrone.Api/packages.config
index 639265482..b000c1262 100644
--- a/NzbDrone.Api/packages.config
+++ b/NzbDrone.Api/packages.config
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="AutoMapper" version="2.2.1" targetFramework="net40" />
-  <package id="FluentValidation" version="3.4.6.0" targetFramework="net40" />
+  <package id="FluentValidation" version="4.0.0.0" targetFramework="net40" />
   <package id="Nancy" version="0.16.1" targetFramework="net40" />
   <package id="Newtonsoft.Json" version="5.0.3" targetFramework="net40" />
   <package id="NLog" version="2.0.1.2" targetFramework="net40" />
diff --git a/NzbDrone.Integration.Test/NzbDrone.Integration.Test.csproj b/NzbDrone.Integration.Test/NzbDrone.Integration.Test.csproj
index c5ffa7733..dffa6e04e 100644
--- a/NzbDrone.Integration.Test/NzbDrone.Integration.Test.csproj
+++ b/NzbDrone.Integration.Test/NzbDrone.Integration.Test.csproj
@@ -36,9 +36,9 @@
     <Reference Include="FluentAssertions">
       <HintPath>..\packages\FluentAssertions.2.0.1\lib\net40\FluentAssertions.dll</HintPath>
     </Reference>
-    <Reference Include="FluentValidation, Version=3.4.6.0, Culture=neutral, processorArchitecture=MSIL">
+    <Reference Include="FluentValidation, Version=4.0.0.0, Culture=neutral, processorArchitecture=MSIL">
       <SpecificVersion>False</SpecificVersion>
-      <HintPath>..\packages\FluentValidation.3.4.6.0\lib\Net40\FluentValidation.dll</HintPath>
+      <HintPath>..\packages\FluentValidation.4.0.0.0\lib\Net40\FluentValidation.dll</HintPath>
     </Reference>
     <Reference Include="Nancy">
       <HintPath>..\packages\Nancy.0.16.1\lib\net40\Nancy.dll</HintPath>
diff --git a/NzbDrone.Integration.Test/packages.config b/NzbDrone.Integration.Test/packages.config
index 336904e91..6dbf1fc7e 100644
--- a/NzbDrone.Integration.Test/packages.config
+++ b/NzbDrone.Integration.Test/packages.config
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="FluentAssertions" version="2.0.1" targetFramework="net40" />
-  <package id="FluentValidation" version="3.4.6.0" targetFramework="net40" />
+  <package id="FluentValidation" version="4.0.0.0" targetFramework="net40" />
   <package id="Nancy" version="0.16.1" targetFramework="net40" />
   <package id="Nancy.Hosting.Self" version="0.16.1" targetFramework="net40" />
   <package id="Newtonsoft.Json" version="5.0.3" targetFramework="net40" />