diff --git a/src/Mapper.hpp b/src/Mapper.hpp
index 11b68e4..6d18b7a 100644
--- a/src/Mapper.hpp
+++ b/src/Mapper.hpp
@@ -10,6 +10,8 @@ class Mapper
 	friend class PatternTableViewer;
 
 public:
+	virtual ~Mapper() {}
+
 	virtual Byte ReadCPU(Word addr) = 0;
 	virtual Byte ReadPPU(Word addr) = 0;
 	virtual void WriteCPU(Word addr, Byte val) = 0;