diff --git a/Source/cbzip2.h b/Source/cbzip2.h
index 6e50a86b..f908d9a7 100644
--- a/Source/cbzip2.h
+++ b/Source/cbzip2.h
@@ -6,6 +6,8 @@
 
 class CBzip2 : public ICompressor {
   public:
+    virtual ~CBzip2() {}
+
     int Init(int level, unsigned int dict_size) {
       last_ret = !BZ_STREAM_END;
       stream = new bz_stream;
diff --git a/Source/compressor.h b/Source/compressor.h
index 0f0649a7..e8a677f2 100644
--- a/Source/compressor.h
+++ b/Source/compressor.h
@@ -6,6 +6,8 @@
 
 class ICompressor {
   public:
+    virtual ~ICompressor() {}
+
     virtual int Init(int level, unsigned int dict_size) = 0;
     virtual int End() = 0;
     virtual int Compress(bool finish) = 0;
diff --git a/Source/czlib.h b/Source/czlib.h
index eb98985f..2b19db25 100644
--- a/Source/czlib.h
+++ b/Source/czlib.h
@@ -6,6 +6,8 @@
 
 class CZlib : public ICompressor {
   public:
+    virtual ~CZlib() {}
+
     int Init(int level, unsigned int dict_size) {
       stream = new z_stream;
       if (!stream) return Z_MEM_ERROR;