diff --git a/src/ast/ast_smt2_pp.cpp b/src/ast/ast_smt2_pp.cpp
index ed634069c..db2043320 100644
--- a/src/ast/ast_smt2_pp.cpp
+++ b/src/ast/ast_smt2_pp.cpp
@@ -343,7 +343,7 @@ format * smt2_pp_environment::pp_str_literal(app * t) {
         } else {
             // general hex escape
             buf << "\\x";
-            unsigned int cVal = (unsigned int)c;
+            unsigned int cVal = ((unsigned int)c) & 0x000000FF;
             const char convtable[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
             unsigned int highPart = cVal / 16;
             unsigned int lowPart = cVal % 16;