diff --git a/format.cc b/format.cc
index caddd3ad..f72cbbcd 100644
--- a/format.cc
+++ b/format.cc
@@ -160,6 +160,12 @@ void fmt::BasicWriter<Char>::FormatDecimal(
   buffer[0] = internal::DIGITS[index];
 }
 
+template <typename Char>
+void fmt::BasicWriter<Char>::FormatDecimal(
+    CharPtr buffer, unsigned long long value, unsigned num_digits) {
+    return fmt::BasicWriter<Char>::FormatDecimal(buffer, static_cast<uint64_t>(value), num_digits);
+}
+
 template <typename Char>
 typename fmt::BasicWriter<Char>::CharPtr
   fmt::BasicWriter<Char>::PrepareFilledBuffer(
@@ -400,7 +406,7 @@ void fmt::BasicFormatter<Char>::CheckSign(const Char *&s, const Arg &arg) {
     ReportError(s,
         Format("format specifier '{0}' requires numeric argument") << *s);
   }
-  if (arg.type == UINT || arg.type == ULONG) {
+  if (arg.type == UINT || arg.type == ULONG || arg.type == ULLONG) {
     ReportError(s,
         Format("format specifier '{0}' requires signed argument") << *s);
   }
@@ -519,7 +525,7 @@ void fmt::BasicFormatter<Char>::DoFormat() {
           ++s;
           ++num_open_braces_;
           const Arg &precision_arg = ParseArgIndex(s);
-          unsigned long value = 0;
+          unsigned long long value = 0;
           switch (precision_arg.type) {
           case INT:
             if (precision_arg.int_value < 0)
@@ -537,6 +543,9 @@ void fmt::BasicFormatter<Char>::DoFormat() {
           case ULONG:
             value = precision_arg.ulong_value;
             break;
+          case ULLONG:
+            value = precision_arg.ulong_long_value;
+            break;            
           default:
             ReportError(s, "precision is not integer");
           }
@@ -578,6 +587,9 @@ void fmt::BasicFormatter<Char>::DoFormat() {
     case ULONG:
       writer.FormatInt(arg.ulong_value, spec);
       break;
+    case ULLONG:
+      writer.FormatInt(arg.ulong_long_value, spec);
+      break;      
     case DOUBLE:
       writer.FormatDouble(arg.double_value, spec, precision);
       break;
@@ -655,6 +667,9 @@ template fmt::BasicWriter<char>::CharPtr
 template void fmt::BasicWriter<char>::FormatDecimal(
     CharPtr buffer, uint64_t value, unsigned num_digits);
 
+template void fmt::BasicWriter<char>::FormatDecimal(
+    CharPtr buffer, unsigned long long value, unsigned num_digits);
+
 template fmt::BasicWriter<char>::CharPtr
   fmt::BasicWriter<char>::PrepareFilledBuffer(
     unsigned size, const AlignSpec &spec, char sign);
@@ -687,6 +702,9 @@ template fmt::BasicWriter<wchar_t>::CharPtr
 template void fmt::BasicWriter<wchar_t>::FormatDecimal(
     CharPtr buffer, uint64_t value, unsigned num_digits);
 
+template void fmt::BasicWriter<wchar_t>::FormatDecimal(
+    CharPtr buffer, unsigned long long value, unsigned num_digits);
+
 template fmt::BasicWriter<wchar_t>::CharPtr
   fmt::BasicWriter<wchar_t>::PrepareFilledBuffer(
     unsigned size, const AlignSpec &spec, char sign);
diff --git a/format.h b/format.h
index d7c2b9f4..618484eb 100644
--- a/format.h
+++ b/format.h
@@ -189,6 +189,9 @@ struct SignedIntTraits {
 template <>
 struct IntTraits<int> : SignedIntTraits<int, unsigned> {};
 
+template <>
+struct IntTraits<uint32_t> : SignedIntTraits<uint32_t, unsigned> {};
+
 template <>
 struct IntTraits<long> : SignedIntTraits<long, unsigned long> {};
 
@@ -444,6 +447,7 @@ DEFINE_INT_FORMATTERS(int)
 DEFINE_INT_FORMATTERS(long)
 DEFINE_INT_FORMATTERS(unsigned)
 DEFINE_INT_FORMATTERS(unsigned long)
+DEFINE_INT_FORMATTERS(unsigned long long)
 
 template <typename Char>
 class BasicFormatter;
@@ -500,6 +504,9 @@ class BasicWriter {
   static void FormatDecimal(
       CharPtr buffer, uint64_t value, unsigned num_digits);
 
+  static void FormatDecimal(
+      CharPtr buffer, unsigned long long value, unsigned num_digits);  
+
   static CharPtr FillPadding(CharPtr buffer,
       unsigned total_size, std::size_t content_size, wchar_t fill);
 
@@ -811,7 +818,7 @@ class BasicFormatter {
 
   enum Type {
     // Numeric types should go first.
-    INT, UINT, LONG, ULONG, DOUBLE, LONG_DOUBLE,
+    INT, UINT, LONG, ULONG, ULLONG, DOUBLE, LONG_DOUBLE,
     LAST_NUMERIC_TYPE = LONG_DOUBLE,
     CHAR, STRING, WSTRING, POINTER, CUSTOM
   };
@@ -846,6 +853,7 @@ class BasicFormatter {
       double double_value;
       long long_value;
       unsigned long ulong_value;
+      unsigned long long ulong_long_value;
       long double long_double_value;
       const void *pointer_value;
       struct {
@@ -865,6 +873,7 @@ class BasicFormatter {
     Arg(unsigned value) : type(UINT), uint_value(value), formatter(0) {}
     Arg(long value) : type(LONG), long_value(value), formatter(0) {}
     Arg(unsigned long value) : type(ULONG), ulong_value(value), formatter(0) {}
+    Arg(unsigned long long value) : type(ULLONG), ulong_long_value(value), formatter(0) {}
     Arg(float value) : type(DOUBLE), double_value(value), formatter(0) {}
     Arg(double value) : type(DOUBLE), double_value(value), formatter(0) {}
     Arg(long double value)
@@ -1148,7 +1157,7 @@ class FormatInt {
   enum {BUFFER_SIZE = std::numeric_limits<uint64_t>::digits10 + 3};
   char buffer_[BUFFER_SIZE];
   char *str_;
-
+ 
   // Formats value in reverse and returns the number of digits.
   char *FormatDecimal(uint64_t value) {
     char *buffer_end = buffer_ + BUFFER_SIZE;
@@ -1183,6 +1192,8 @@ class FormatInt {
       *--str_ = '-';
   }
   explicit FormatInt(unsigned value) : str_(FormatDecimal(value)) {}
+  explicit FormatInt(uint64_t value) : str_(FormatDecimal(value)) {}
+  explicit FormatInt(unsigned long long value) : str_(FormatDecimal(value)) {}
 
   const char *c_str() const { return str_; }
   std::string str() const { return str_; }