diff --git a/double-conversion/string-to-double.cc b/double-conversion/string-to-double.cc
index 41e647c4..d83d6ddb 100644
--- a/double-conversion/string-to-double.cc
+++ b/double-conversion/string-to-double.cc
@@ -670,6 +670,7 @@ double StringToDoubleConverter::StringToIeee(
   }
 
   bool leading_zero = false;
+  bool multiple_leading_zeros = false;
   if (*current == '0') {
     if (Advance(&current, separator_, 10, end)) {
       *processed_characters_count = static_cast<int>(current - input);
@@ -716,6 +717,7 @@ double StringToDoubleConverter::StringToIeee(
 
     // Ignore leading zeros in the integer part.
     while (*current == '0') {
+      multiple_leading_zeros = true;
       if (Advance(&current, separator_, 10, end)) {
         *processed_characters_count = static_cast<int>(current - input);
         return SignedZero(sign);
@@ -747,7 +749,9 @@ double StringToDoubleConverter::StringToIeee(
   }
 
   if (significant_digits == 0) {
-    octal = false;
+    if (!multiple_leading_zeros) {
+      octal = false;
+    }
   }
 
   if (*current == '.') {
@@ -882,19 +886,23 @@ double StringToDoubleConverter::StringToIeee(
 
   if (octal) {
     double result;
-    bool result_is_junk;
-    char* start = buffer;
-    result = RadixStringToIeee<3>(&start,
-                                  buffer + buffer_pos,
-                                  sign,
-                                  separator_,
-                                  false, // Don't parse as hex_float.
-                                  allow_trailing_junk,
-                                  allow_trailing_spaces,
-                                  junk_string_value_,
-                                  read_as_double,
-                                  &result_is_junk);
-    DOUBLE_CONVERSION_ASSERT(!result_is_junk);
+    if (buffer_pos == 0) {
+      result = SignedZero(sign);
+    } else {
+      bool result_is_junk;
+      char* start = buffer;
+      result = RadixStringToIeee<3>(&start,
+                                    buffer + buffer_pos,
+                                    sign,
+                                    separator_,
+                                    false, // Don't parse as hex_float.
+                                    allow_trailing_junk,
+                                    allow_trailing_spaces,
+                                    junk_string_value_,
+                                    read_as_double,
+                                    &result_is_junk);
+      DOUBLE_CONVERSION_ASSERT(!result_is_junk);
+    }
     *processed_characters_count = static_cast<int>(current - input);
     return result;
   }
diff --git a/test/cctest/test-conversions.cc b/test/cctest/test-conversions.cc
index 0daf7919..7e41dcb8 100644
--- a/test/cctest/test-conversions.cc
+++ b/test/cctest/test-conversions.cc
@@ -3596,6 +3596,20 @@ TEST(StringToDoubleOctalString) {
            StrToD("01234567e0", flags, Double::NaN(), &processed, &all_used));
   CHECK_EQ(0, processed);
 
+  CHECK_EQ(Double::NaN(),
+           StrToD("00.5", flags, Double::NaN(), &processed, &all_used));
+  CHECK_EQ(0, processed);
+
+  CHECK_EQ(Double::NaN(),
+           StrToD("00e2", flags, Double::NaN(), &processed, &all_used));
+  CHECK_EQ(0, processed);
+
+  CHECK_EQ(0.5, StrToD("0.5", flags, Double::NaN(), &processed, &all_used));
+  CHECK(all_used);
+
+  CHECK_EQ(8.5, StrToD("008.5", flags, Double::NaN(), &processed, &all_used));
+  CHECK(all_used);
+
 
   flags = StringToDoubleConverter::ALLOW_OCTALS |
       StringToDoubleConverter::ALLOW_TRAILING_JUNK;
@@ -3753,6 +3767,14 @@ TEST(StringToDoubleOctalString) {
            StrToD("01234567e", flags, Double::NaN(), &processed, &all_used));
   CHECK_EQ(8, processed);
 
+  CHECK_EQ(0.0,
+           StrToD("00.5", flags, Double::NaN(), &processed, &all_used));
+  CHECK_EQ(2, processed);
+
+  CHECK_EQ(0.0,
+           StrToD("00e2", flags, Double::NaN(), &processed, &all_used));
+  CHECK_EQ(2, processed);
+
   flags = StringToDoubleConverter::ALLOW_OCTALS |
       StringToDoubleConverter::ALLOW_TRAILING_SPACES |
       StringToDoubleConverter::ALLOW_TRAILING_JUNK;