diff --git a/NLog.Target.Gelf/GelfMessage.cs b/NLog.Target.Gelf/GelfMessage.cs
index 9c990b8..0973beb 100644
--- a/NLog.Target.Gelf/GelfMessage.cs
+++ b/NLog.Target.Gelf/GelfMessage.cs
@@ -1,3 +1,4 @@
+using System.Collections.Generic;
 using Newtonsoft.Json;
 
 namespace NLog.Targets.Gelf
@@ -34,5 +35,8 @@ internal class GelfMessage
 
         [JsonProperty("_notes")]
         public string Notes { get; set; }
+
+        [JsonExtensionData]
+        public Dictionary<string, object> Properties { get; set; }
     }
 }
\ No newline at end of file
diff --git a/NLog.Target.Gelf/NLog.Targets.Gelf.cs b/NLog.Target.Gelf/NLog.Targets.Gelf.cs
index dcb28ed..734ee65 100644
--- a/NLog.Target.Gelf/NLog.Targets.Gelf.cs
+++ b/NLog.Target.Gelf/NLog.Targets.Gelf.cs
@@ -142,7 +142,8 @@ private string CreateGelfJsonFromLoggingEvent(LogEventInfo logEventInfo)
                     Host = Dns.GetHostName(),
                     Level = logEventInfo.Level.GelfSeverity(),
                     ShortMessage = shortMessage,
-                    Logger = logEventInfo.LoggerName ?? ""
+                    Logger = logEventInfo.LoggerName ?? "",
+                    Properties = logEventInfo.Properties.ToDictionary(x => "_" + x.Key, y => y.Value)
                 };
 
             if (logEventInfo.Properties != null)
diff --git a/TestApp/Form1.Designer.cs b/TestApp/Form1.Designer.cs
index 9dc78bd..b6be99b 100644
--- a/TestApp/Form1.Designer.cs
+++ b/TestApp/Form1.Designer.cs
@@ -39,6 +39,7 @@ private void InitializeComponent()
             this.lblRandomMessageSize = new System.Windows.Forms.Label();
             this.buttonCustomMessage = new System.Windows.Forms.Button();
             this.tbxCustomMessage = new System.Windows.Forms.TextBox();
+            this.buttonCustomFields = new System.Windows.Forms.Button();
             this.SuspendLayout();
             // 
             // buttonTrace
@@ -103,7 +104,7 @@ private void InitializeComponent()
             // 
             // buttonRandomMessage
             // 
-            this.buttonRandomMessage.Location = new System.Drawing.Point(34, 290);
+            this.buttonRandomMessage.Location = new System.Drawing.Point(34, 334);
             this.buttonRandomMessage.Name = "buttonRandomMessage";
             this.buttonRandomMessage.Size = new System.Drawing.Size(212, 38);
             this.buttonRandomMessage.TabIndex = 6;
@@ -113,7 +114,7 @@ private void InitializeComponent()
             // 
             // tbxRandomMessageSize
             // 
-            this.tbxRandomMessageSize.Location = new System.Drawing.Point(153, 334);
+            this.tbxRandomMessageSize.Location = new System.Drawing.Point(153, 378);
             this.tbxRandomMessageSize.MaxLength = 7;
             this.tbxRandomMessageSize.Name = "tbxRandomMessageSize";
             this.tbxRandomMessageSize.Size = new System.Drawing.Size(93, 20);
@@ -122,7 +123,7 @@ private void InitializeComponent()
             // lblRandomMessageSize
             // 
             this.lblRandomMessageSize.AutoSize = true;
-            this.lblRandomMessageSize.Location = new System.Drawing.Point(31, 337);
+            this.lblRandomMessageSize.Location = new System.Drawing.Point(31, 381);
             this.lblRandomMessageSize.Name = "lblRandomMessageSize";
             this.lblRandomMessageSize.Size = new System.Drawing.Size(116, 13);
             this.lblRandomMessageSize.TabIndex = 8;
@@ -130,7 +131,7 @@ private void InitializeComponent()
             // 
             // buttonCustomMessage
             // 
-            this.buttonCustomMessage.Location = new System.Drawing.Point(34, 360);
+            this.buttonCustomMessage.Location = new System.Drawing.Point(34, 404);
             this.buttonCustomMessage.Name = "buttonCustomMessage";
             this.buttonCustomMessage.Size = new System.Drawing.Size(212, 38);
             this.buttonCustomMessage.TabIndex = 9;
@@ -140,17 +141,28 @@ private void InitializeComponent()
             // 
             // tbxCustomMessage
             // 
-            this.tbxCustomMessage.Location = new System.Drawing.Point(34, 404);
+            this.tbxCustomMessage.Location = new System.Drawing.Point(34, 448);
             this.tbxCustomMessage.Multiline = true;
             this.tbxCustomMessage.Name = "tbxCustomMessage";
             this.tbxCustomMessage.Size = new System.Drawing.Size(212, 236);
             this.tbxCustomMessage.TabIndex = 10;
             // 
+            // buttonCustomFields
+            // 
+            this.buttonCustomFields.Location = new System.Drawing.Point(34, 290);
+            this.buttonCustomFields.Name = "buttonCustomFields";
+            this.buttonCustomFields.Size = new System.Drawing.Size(212, 38);
+            this.buttonCustomFields.TabIndex = 11;
+            this.buttonCustomFields.Text = "Custom Fields";
+            this.buttonCustomFields.UseVisualStyleBackColor = true;
+            this.buttonCustomFields.Click += new System.EventHandler(this.ButtonLog_Click);
+            // 
             // Form1
             // 
             this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
             this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
-            this.ClientSize = new System.Drawing.Size(284, 652);
+            this.ClientSize = new System.Drawing.Size(284, 721);
+            this.Controls.Add(this.buttonCustomFields);
             this.Controls.Add(this.tbxCustomMessage);
             this.Controls.Add(this.buttonCustomMessage);
             this.Controls.Add(this.lblRandomMessageSize);
@@ -186,6 +198,7 @@ private void InitializeComponent()
         private System.Windows.Forms.Label lblRandomMessageSize;
         private System.Windows.Forms.Button buttonCustomMessage;
         private System.Windows.Forms.TextBox tbxCustomMessage;
+        private System.Windows.Forms.Button buttonCustomFields;
     }
 }
 
diff --git a/TestApp/Form1.cs b/TestApp/Form1.cs
index 2f420cd..af2828f 100644
--- a/TestApp/Form1.cs
+++ b/TestApp/Form1.cs
@@ -48,6 +48,9 @@ private void ButtonLog_Click(object sender, EventArgs e)
                 case "buttonFatal":
                     Logger.Fatal("This is a sample fatal message");
                     break;
+                case "buttonCustomFields":
+                    LogEventWithCustomProperties(LogLevel.Trace, "This is a message with custom fields");
+                    break;
                 case "buttonRandomMessage":
                     // 32 is a space, the rest are the upper case alphabet.
                     var byteValues = new[] {32, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90};
@@ -65,5 +68,13 @@ private void ButtonLog_Click(object sender, EventArgs e)
                     break;
             }
         }
+
+        private static void LogEventWithCustomProperties(LogLevel level, string message)
+        {
+            var theEvent = new LogEventInfo(level, "logger-name", message);
+            theEvent.Properties["MyCustomValue"] = "custom";
+            theEvent.Properties["AnotherCustomValue"] = "custom2";
+            Logger.Log(theEvent);
+        }
     }
 }