diff --git a/NzbDrone.Web/Helpers/Validation/RequiredIfAnyAttribute.cs b/NzbDrone.Web/Helpers/Validation/RequiredIfAnyAttribute.cs
new file mode 100644
index 000000000..e0ccf3ce6
--- /dev/null
+++ b/NzbDrone.Web/Helpers/Validation/RequiredIfAnyAttribute.cs
@@ -0,0 +1,101 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using System.Web;
+using System.Web.Mvc;
+
+namespace NzbDrone.Web.Helpers.Validation
+{
+    public class RequiredIfAnyAttribute : ValidationAttribute, IClientValidatable
+    {
+        private RequiredAttribute _innerAttribute = new RequiredAttribute();
+
+        public string[] DependentProperties { get; set; }
+        public object[] TargetValues { get; set; }
+
+        public RequiredIfAnyAttribute(string[] dependentProperties, params object[] targetValues)
+        {
+            if (dependentProperties.Count() != targetValues.Count())
+                throw new ArgumentException("Dependent properties count must equal values count");
+
+            this.DependentProperties = dependentProperties;
+            this.TargetValues = targetValues;
+        }
+
+        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
+        {
+            for (int i = 0; i < DependentProperties.Count(); i++)
+            {
+                // get a reference to the property this validation depends upon
+                var containerType = validationContext.ObjectInstance.GetType();
+                var field = containerType.GetProperty(this.DependentProperties[i]);
+
+                if (field != null)
+                {
+                    // get the value of the dependent property
+                    var dependentvalue = field.GetValue(validationContext.ObjectInstance, null);
+
+                    // compare the value against the target value
+                    if ((dependentvalue == null && this.TargetValues[i] == null) ||
+                        (dependentvalue != null && dependentvalue.Equals(this.TargetValues[i])))
+                    {
+                        // match => means we should try validating this field
+                        if (!_innerAttribute.IsValid(value))
+                            // validation failed - return an error
+                            return new ValidationResult(this.ErrorMessage, new[] { validationContext.MemberName });
+                    }
+                }
+            }
+
+            return ValidationResult.Success;
+        }
+
+        public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
+        {
+            var rule = new ModelClientValidationRule()
+            {
+                ErrorMessage = FormatErrorMessage(metadata.GetDisplayName()),
+                ValidationType = "requiredifany",
+            };
+
+            var properties = new List<string>();
+            var values = new List<object>();
+
+            for (int i = 0; i < DependentProperties.Count(); i++)
+            {
+                string depProp = BuildDependentPropertyId(metadata, context as ViewContext, DependentProperties[i]);
+
+                // find the value on the control we depend on;
+                // if it's a bool, format it javascript style 
+                // (the default is True or False!)
+                string targetValue = (TargetValues[i] ?? "").ToString();
+                if (TargetValues[i].GetType() == typeof(bool))
+                    targetValue = targetValue.ToLower();
+
+                properties.Add(depProp);
+                values.Add(targetValue);
+            }
+
+            rule.ValidationParameters.Add("dependentproperties", String.Join("|", properties));
+            rule.ValidationParameters.Add("targetvalues", String.Join("|", values));
+
+            yield return rule;
+        }
+
+        private string BuildDependentPropertyId(ModelMetadata metadata, ViewContext viewContext, string dependentProperty)
+        {
+            // build the ID of the property
+            string depProp = viewContext.ViewData.TemplateInfo.GetFullHtmlFieldId(dependentProperty);
+            // unfortunately this will have the name of the current field appended to the beginning,
+            // because the TemplateInfo's context has had this fieldname appended to it. Instead, we
+            // want to get the context as though it was one level higher (i.e. outside the current property,
+            // which is the containing object (our Person), and hence the same level as the dependent property.
+            var thisField = metadata.PropertyName + "_";
+            if (depProp.StartsWith(thisField))
+                // strip it off again
+                depProp = depProp.Substring(thisField.Length);
+            return depProp;
+        }
+    }
+}
\ No newline at end of file
diff --git a/NzbDrone.Web/Models/NotificationSettingsModel.cs b/NzbDrone.Web/Models/NotificationSettingsModel.cs
index d9596e2b3..02e7d2540 100644
--- a/NzbDrone.Web/Models/NotificationSettingsModel.cs
+++ b/NzbDrone.Web/Models/NotificationSettingsModel.cs
@@ -201,7 +201,7 @@ namespace NzbDrone.Web.Models
         [DataType(DataType.Text)]
         [DisplayName("Client Hosts")]
         [Description("Plex client hosts with port, comma separated for multiple clients")]
-        [RequiredIf("PlexNotifyOnGrab", true, ErrorMessage = "Required when Plex Notifications are enabled")]
+        [RequiredIfAny(new string[]{ "PlexNotifyOnGrab", "PlexNotifyOnDownload" }, new object[]{ true, true }, ErrorMessage = "Required when Plex Notifications are enabled")]
         [DisplayFormat(ConvertEmptyStringToNull = false)]
         public string PlexClientHosts { get; set; }
 
diff --git a/NzbDrone.Web/NzbDrone.Web.csproj b/NzbDrone.Web/NzbDrone.Web.csproj
index af22938c2..776a3069d 100644
--- a/NzbDrone.Web/NzbDrone.Web.csproj
+++ b/NzbDrone.Web/NzbDrone.Web.csproj
@@ -131,6 +131,7 @@
     </Reference>
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Helpers\Validation\RequiredIfAnyAttribute.cs" />
     <Compile Include="Helpers\Validation\RequiredIfAttribute.cs" />
     <Content Include="Content\DataTables-1.9.0\media\css\jquery.dataTables.css" />
     <Content Include="Content\DataTables-1.9.0\media\images\back_disabled.png" />
diff --git a/NzbDrone.Web/Scripts/conditional-validation.js b/NzbDrone.Web/Scripts/conditional-validation.js
index 6c6421726..5797cdce9 100644
--- a/NzbDrone.Web/Scripts/conditional-validation.js
+++ b/NzbDrone.Web/Scripts/conditional-validation.js
@@ -40,4 +40,54 @@ $.validator.unobtrusive.adapters.add(
             targetvalue: options.params['targetvalue']
         };
         options.messages['requiredif'] = options.message;
-    });
+});
+
+
+$.validator.addMethod('requiredifany',
+    function (value, element, parameters) {
+
+        console.log(parameters['dependentproperties']);
+        console.log(parameters['targetvalues']);
+
+        var dependentProperties = parameters['dependentproperties'].split('|');
+        var targetValues = parameters['targetvalues'].split('|');
+
+        for (var i = 0; i < dependentProperties.length; i++) {
+            var id = '#' + dependentProperties[i];
+
+            // get the target value (as a string, 
+            // as that's what actual value will be)
+            var targetvalue = targetValues[i];
+            targetvalue =
+                (targetvalue == null ? '' : targetvalue).toString();
+
+            // get the actual value of the target control
+            // note - this probably needs to cater for more 
+            // control types, e.g. radios
+            var control = $(id);
+            var controltype = control.attr('type');
+            var actualvalue =
+                controltype === 'checkbox' ?
+                    (control.attr('checked') == "checked" ? "true" : "false") :
+                    control.val();
+
+            // if the condition is true, reuse the existing 
+            // required field validator functionality
+            if (targetvalue === actualvalue)
+                return $.validator.methods.required.call(
+                    this, value, element, parameters);
+        }
+        return true;
+    }
+);
+
+    $.validator.unobtrusive.adapters.add(
+    'requiredifany',
+    ['dependentproperties', 'targetvalues'],
+    function (options) {
+        options.rules['requiredifany'] = {
+            dependentproperties: options.params['dependentproperties'],
+            targetvalues: options.params['targetvalues']
+        };
+        options.messages['requiredifany'] = options.message;
+    });
\ No newline at end of file