diff --git a/src/goto-programs/interpreter.cpp b/src/goto-programs/interpreter.cpp
index b624db34357..a2de956dabd 100644
--- a/src/goto-programs/interpreter.cpp
+++ b/src/goto-programs/interpreter.cpp
@@ -16,7 +16,7 @@ Author: Daniel Kroening, kroening@kroening.com
 #include <iostream>
 #include <fstream>
 #include <algorithm>
-#include <string.h>
+#include <cstring>
 
 #include <util/invariant.h>
 #include <util/std_types.h>
diff --git a/src/goto-programs/interpreter_evaluate.cpp b/src/goto-programs/interpreter_evaluate.cpp
index 10b352090c3..b1c87a48039 100644
--- a/src/goto-programs/interpreter_evaluate.cpp
+++ b/src/goto-programs/interpreter_evaluate.cpp
@@ -13,13 +13,13 @@ Author: Daniel Kroening, kroening@kroening.com
 
 #include <iostream>
 #include <sstream>
+#include <cstring>
 
 #include <util/ieee_float.h>
 #include <util/invariant.h>
 #include <util/fixedbv.h>
 #include <util/std_expr.h>
 #include <util/pointer_offset_size.h>
-#include <string.h>
 
 /// Reads a memory address and loads it into the `dest` variable.
 /// Marks cell as `READ_BEFORE_WRITTEN` if cell has never been written.
diff --git a/src/solvers/prop/prop.h b/src/solvers/prop/prop.h
index fc43f6683ea..7ac5d88848e 100644
--- a/src/solvers/prop/prop.h
+++ b/src/solvers/prop/prop.h
@@ -12,7 +12,7 @@ Author: Daniel Kroening, kroening@kroening.com
 
 // decision procedure wrapper for boolean propositional logics
 
-#include <stdint.h>
+#include <cstdint>
 
 #include <util/message.h>
 #include <util/threeval.h>