diff --git a/src/NPoco/Expressions/SqlExpression.cs b/src/NPoco/Expressions/SqlExpression.cs
index fd810da3..44aac018 100644
--- a/src/NPoco/Expressions/SqlExpression.cs
+++ b/src/NPoco/Expressions/SqlExpression.cs
@@ -1092,6 +1092,11 @@ protected virtual object VisitConditional(ConditionalExpression conditional)
 
         protected string CreateParam(object value)
         {
+            // If value has already been provided, reuse the parameter.
+            var indexOfExistingValue = _params.IndexOf(value);
+            if (indexOfExistingValue >= 0)
+                return paramPrefix + indexOfExistingValue;
+
             string paramPlaceholder = paramPrefix + _params.Count;
             _params.Add(value);
             return paramPlaceholder;