diff --git a/include/vigra/random_forest/rf_ridge_split.hxx b/include/vigra/random_forest/rf_ridge_split.hxx
--- a/include/vigra/random_forest/rf_ridge_split.hxx
+++ b/include/vigra/random_forest/rf_ridge_split.hxx
@@ -80,7 +80,7 @@ class RidgeSplit: public SplitBase<Tag>
 
 	double                      region_gini_;
 	ArrayVector<double>         min_gini_;
-	ArrayVector<ptrdiff_t>      min_indices_;
+	ArrayVector<std::ptrdiff_t>      min_indices_;
 	ArrayVector<double>         min_thresholds_;
 
 	int                         bestSplitIndex;
diff --git a/include/vigra/random_forest/rf_split.hxx b/include/vigra/random_forest/rf_split.hxx
--- a/include/vigra/random_forest/rf_split.hxx
+++ b/include/vigra/random_forest/rf_split.hxx
@@ -676,7 +676,7 @@ public:
     ArrayVector<double>     class_weights_;
     ArrayVector<double>     bestCurrentCounts[2];
     double                  min_gini_;
-    ptrdiff_t               min_index_;
+    std::ptrdiff_t               min_index_;
     double                  min_threshold_;
     ProblemSpec<>           ext_param_;
 
@@ -811,7 +811,7 @@ class ThresholdSplit: public SplitBase<T
 
     double                      region_gini_;
     ArrayVector<double>         min_gini_;
-    ArrayVector<ptrdiff_t>      min_indices_;
+    ArrayVector<std::ptrdiff_t>      min_indices_;
     ArrayVector<double>         min_thresholds_;
 
     int                         bestSplitIndex;
@@ -984,7 +984,7 @@ public:
     ArrayVector<double>     class_weights_;
     ArrayVector<double>     bestCurrentCounts[2];
     double                  min_gini_;
-    ptrdiff_t               min_index_;
+    std::ptrdiff_t               min_index_;
     double                  min_threshold_;
     ProblemSpec<>           ext_param_;
 
@@ -1085,7 +1085,7 @@ public:
     ArrayVector<double>     class_weights_;
     ArrayVector<double>     bestCurrentCounts[2];
     double                  min_gini_;
-    ptrdiff_t               min_index_;
+    std::ptrdiff_t               min_index_;
     double                  min_threshold_;
     ProblemSpec<>           ext_param_;
 	typedef RandomMT19937	Random_t;
diff --git a/include/vigra/sifImport.hxx b/include/vigra/sifImport.hxx
--- a/include/vigra/sifImport.hxx
+++ b/include/vigra/sifImport.hxx
@@ -113,7 +113,7 @@ class SIFImportInfo
          *  Everything before this point belongs to the 
          *  variable lenght header.
          **/
-		VIGRA_EXPORT const ptrdiff_t getOffset() const;
+		VIGRA_EXPORT const std::ptrdiff_t getOffset() const;
 
         /** Get the filename of this SIF object.
          **/
@@ -140,7 +140,7 @@ class SIFImportInfo
 		int m_width;
 		int m_height;
 		int m_stacksize;
-		ptrdiff_t m_offset;
+		std::ptrdiff_t m_offset;
 		int mod;
 		int left, right, bottom, top;
 		int xbin, ybin, xres, yres;
diff --git a/src/impex/sifImport.cxx b/src/impex/sifImport.cxx
--- a/src/impex/sifImport.cxx
+++ b/src/impex/sifImport.cxx
@@ -116,7 +116,7 @@ inline std::string toString(double x) {
 const int SIFImportInfo::width() const {	return m_width; }
 const int SIFImportInfo::height() const {	return m_height; }
 const int SIFImportInfo::stacksize() const {	return m_stacksize; }
-const ptrdiff_t SIFImportInfo::getOffset() const {	return m_offset; }
+const std::ptrdiff_t SIFImportInfo::getOffset() const {	return m_offset; }
 const char * SIFImportInfo::getFileName() const  {	return m_filename;	}	
 
 
@@ -245,7 +245,7 @@ void readSIF(const SIFImportInfo &info, 
 
 	byteorder bo = byteorder("little endian");  // SIF file is little-endian
 
-	ptrdiff_t pos = file.tellg();		// pointer to beginning of the file
+	std::ptrdiff_t pos = file.tellg();		// pointer to beginning of the file
 	file.seekg(pos+info.getOffset());
 	read_array( file, bo, memblock, info.width()*info.height()*info.stacksize() );
 	file.close();
diff --git a/test/utilities/test.cxx b/test/utilities/test.cxx
--- a/test/utilities/test.cxx
+++ b/test/utilities/test.cxx
@@ -217,8 +217,8 @@ struct ArrayVectorTest
 
     void testAmbiguousConstructor()
     {
-        ArrayVector<ptrdiff_t> a(2, ptrdiff_t(1));
-        ArrayVector<ptrdiff_t> b(a.begin(), a.end());
+        ArrayVector<std::ptrdiff_t> a(2, ptrdiff_t(1));
+        ArrayVector<std::ptrdiff_t> b(a.begin(), a.end());
     }
 };