diff --git a/src/SharpNeatLib/Network/ActivationFunctions/ActivationFunctionRegistry.cs b/src/SharpNeatLib/Network/ActivationFunctions/ActivationFunctionRegistry.cs
new file mode 100644
index 00000000..139a5e18
--- /dev/null
+++ b/src/SharpNeatLib/Network/ActivationFunctions/ActivationFunctionRegistry.cs
@@ -0,0 +1,78 @@
+/* ***************************************************************************
+ * This file is part of SharpNEAT - Evolution of Neural Networks.
+ * 
+ * Copyright 2004-2016 Colin Green (sharpneat@gmail.com)
+ *
+ * Written by Scott DeBoer, 2019 (naigonakoii@gmail.com)
+ * 
+ * SharpNEAT is free software; you can redistribute it and/or modify
+ * it under the terms of The MIT License (MIT).
+ *
+ * You should have received a copy of the MIT License
+ * along with SharpNEAT; if not, see https://opensource.org/licenses/MIT.
+ */
+using System;
+using System.Collections.Generic;
+
+namespace SharpNeat.Network
+{
+    public static class ActivationFunctionRegistry
+    {
+        // The default set of activation functions.
+        private static Dictionary<string, IActivationFunction> __activationFunctionTable = new Dictionary<string, IActivationFunction>()
+        {
+            // Bipolar.
+            { "BipolarSigmoid", BipolarSigmoid.__DefaultInstance },
+            { "BipolarGaussian", BipolarGaussian.__DefaultInstance },
+            { "Linear", Linear.__DefaultInstance },
+            { "Sine", Sine.__DefaultInstance },
+
+            // Unipolar.
+            { "ArcSinH", ArcSinH.__DefaultInstance },
+            { "ArcTan", ArcTan.__DefaultInstance },
+            { "Gaussian", Gaussian.__DefaultInstance },
+            { "LeakyReLU", LeakyReLU.__DefaultInstance },
+            { "LeakyReLUShifted", LeakyReLUShifted.__DefaultInstance },
+            { "LogisticFunction", LogisticFunction.__DefaultInstance },
+            { "LogisticFunctionSteep", LogisticFunctionSteep.__DefaultInstance },
+            { "MaxMinusOne", MaxMinusOne.__DefaultInstance },
+            { "PolynomialApproximantSteep", PolynomialApproximantSteep.__DefaultInstance },
+            { "QuadraticSigmoid", QuadraticSigmoid.__DefaultInstance },
+            { "ReLU", ReLU.__DefaultInstance },
+            { "ScaledELU", ScaledELU.__DefaultInstance },
+            { "SoftSignSteep", SoftSignSteep.__DefaultInstance },
+            { "SReLU", SReLU.__DefaultInstance },
+            { "SReLUShifted", SReLUShifted.__DefaultInstance },
+            { "TanH", TanH.__DefaultInstance },
+
+            // Radial Basis.
+            { "RbfGaussian", RbfGaussian.__DefaultInstance },
+        };
+
+        #region Public Static Methods
+
+        /// <summary>
+        /// Registers a custom activation function in addition to those in the default activation function table.
+        /// Alows loading of neural nets from XML that use custom activation functions.
+        /// </summary>
+        public static void RegisterActivationFunction(IActivationFunction function)
+        {
+            if(!__activationFunctionTable.ContainsKey(function.FunctionId)) {
+                __activationFunctionTable.Add(function.FunctionId, function);
+            }
+        }
+
+        /// <summary>
+        /// Gets an IActivationFunction with the given short name.
+        /// </summary>
+        public static IActivationFunction GetActivationFunction(string name)
+        {
+            if(!__activationFunctionTable.ContainsKey(name)) {
+                throw new ArgumentException($"Unexpected activation function [{name}]");
+            }
+            return __activationFunctionTable[name];
+        }
+
+        #endregion
+    }
+}
diff --git a/src/SharpNeatLib/Network/NetworkXmlIO.cs b/src/SharpNeatLib/Network/NetworkXmlIO.cs
index c0536e38..39a553c4 100644
--- a/src/SharpNeatLib/Network/NetworkXmlIO.cs
+++ b/src/SharpNeatLib/Network/NetworkXmlIO.cs
@@ -459,7 +459,7 @@ public static IActivationFunctionLibrary ReadActivationFunctionLibrary(XmlReader
                     string fnName = xrSubtree.GetAttribute(__AttrName);
 
                     // Lookup function name.
-                    IActivationFunction activationFn = GetActivationFunction(fnName);
+                    IActivationFunction activationFn = ActivationFunctionRegistry.GetActivationFunction(fnName);
 
                     // Add new function to our list of functions.
                     ActivationFunctionInfo fnInfo = new ActivationFunctionInfo(id, selectionProb, activationFn);
@@ -528,44 +528,6 @@ public static string GetNodeTypeString(NodeType nodeType)
             throw new ArgumentException($"Unexpected NodeType [{nodeType}]");
         }
 
-        /// <summary>
-        /// Gets an IActivationFunction from its short name.
-        /// </summary>
-        public static IActivationFunction GetActivationFunction(string name)
-        {
-            switch(name)
-            {
-                // Bipolar.
-                case "BipolarGaussian": return BipolarGaussian.__DefaultInstance;
-                case "BipolarSigmoid":  return BipolarSigmoid.__DefaultInstance;
-                case "Linear":          return Linear.__DefaultInstance;
-                case "Sine":            return Sine.__DefaultInstance;
-
-                // Unipolar.
-                case "ArcSinH":         return ArcSinH.__DefaultInstance;
-                case "ArcTan":          return ArcTan.__DefaultInstance;
-                case "Gaussian":        return Gaussian.__DefaultInstance;
-                case "LeakyReLU":       return LeakyReLU.__DefaultInstance;
-                case "LeakyReLUShifted":            return LeakyReLUShifted.__DefaultInstance;
-                case "LogisticFunction":            return LogisticFunction.__DefaultInstance;
-                case "LogisticFunctionSteep":       return LogisticFunctionSteep.__DefaultInstance;
-                case "MaxMinusOne":                 return MaxMinusOne.__DefaultInstance;
-                case "PolynomialApproximantSteep":  return PolynomialApproximantSteep.__DefaultInstance;
-                case "QuadraticSigmoid":            return QuadraticSigmoid.__DefaultInstance;
-                case "ReLU":            return ReLU.__DefaultInstance;
-                case "ScaledELU":       return ScaledELU.__DefaultInstance;
-                case "SoftSignSteep":   return SoftSignSteep.__DefaultInstance;
-                case "SReLU":           return SReLU.__DefaultInstance;
-                case "SReLUShifted":    return SReLUShifted.__DefaultInstance;
-                case "TanH":            return TanH.__DefaultInstance;
-
-                // Radial Basis.
-                case "RbfGaussian": return RbfGaussian.__DefaultInstance;
-
-            }
-            throw new ArgumentException($"Unexpected activation function [{name}]");
-        }
-
         #endregion
 
         #region Private Static Methods