diff --git a/src/corelib/text/qbytearray.cpp b/src/corelib/text/qbytearray.cpp
index 03e3f0611a..32e10b9512 100644
--- a/src/corelib/text/qbytearray.cpp
+++ b/src/corelib/text/qbytearray.cpp
@@ -3866,7 +3866,7 @@ QByteArray QByteArray::toBase64(Base64Options options) const
     Sets the byte array to the printed value of \a n in base \a base (ten by
     default) and returns a reference to the byte array. Bases 2 through 36 are
     supported, using letters for digits beyond 9; A is ten, B is eleven and so
-    on. For bases other than ten, n is treated as an unsigned integer.
+    on.
 
     Example:
     \snippet code/src_corelib_text_qbytearray.cpp 40
@@ -3942,7 +3942,8 @@ QByteArray &QByteArray::setNum(qlonglong n, int base)
     char buff[buffsize];
     char *p;
 
-    if (n < 0 && base == 10) {
+    if (n < 0) {
+        // Take care to avoid overflow on negating min value:
         p = qulltoa2(buff + buffsize, qulonglong(-(1 + n)) + 1, base);
         *--p = '-';
     } else {
diff --git a/src/corelib/text/qbytearray.h b/src/corelib/text/qbytearray.h
index 91f50d76c3..2d614f1fe0 100644
--- a/src/corelib/text/qbytearray.h
+++ b/src/corelib/text/qbytearray.h
@@ -598,15 +598,15 @@ inline const QByteArray operator+(char a1, const QByteArray &a2)
 #endif // QT_USE_QSTRINGBUILDER
 
 inline QByteArray &QByteArray::setNum(short n, int base)
-{ return base == 10 ? setNum(qlonglong(n), base) : setNum(qulonglong(ushort(n)), base); }
+{ return setNum(qlonglong(n), base); }
 inline QByteArray &QByteArray::setNum(ushort n, int base)
 { return setNum(qulonglong(n), base); }
 inline QByteArray &QByteArray::setNum(int n, int base)
-{ return base == 10 ? setNum(qlonglong(n), base) : setNum(qulonglong(uint(n)), base); }
+{ return setNum(qlonglong(n), base); }
 inline QByteArray &QByteArray::setNum(uint n, int base)
 { return setNum(qulonglong(n), base); }
 inline QByteArray &QByteArray::setNum(long n, int base)
-{ return base == 10 ? setNum(qlonglong(n), base) : setNum(qulonglong(ulong(n)), base); }
+{ return setNum(qlonglong(n), base); }
 inline QByteArray &QByteArray::setNum(ulong n, int base)
 { return setNum(qulonglong(n), base); }
 inline QByteArray &QByteArray::setNum(float n, char f, int prec)
diff --git a/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp b/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp
index e9d0cf8236..0db139b518 100644
--- a/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp
+++ b/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp
@@ -425,18 +425,17 @@ void tst_QByteArray::setNum()
     QCOMPARE(a.setNum(37, 2), QByteArray("100101"));
     QCOMPARE(a.setNum(37, 36), QByteArray("11"));
 
-    // Negative numbers are only properly supported for base 10.
-    QCOMPARE(a.setNum(short(-1), 16), QByteArray("ffff"));
-    QCOMPARE(a.setNum(int(-1), 16), QByteArray("ffffffff"));
-    QCOMPARE(a.setNum(qlonglong(-1), 16), QByteArray("ffffffffffffffff"));
+    QCOMPARE(a.setNum(short(-1), 16), QByteArray("-1"));
+    QCOMPARE(a.setNum(int(-1), 16), QByteArray("-1"));
+    QCOMPARE(a.setNum(qlonglong(-1), 16), QByteArray("-1"));
 
     QCOMPARE(a.setNum(short(-1), 10), QByteArray("-1"));
     QCOMPARE(a.setNum(int(-1), 10), QByteArray("-1"));
     QCOMPARE(a.setNum(qlonglong(-1), 10), QByteArray("-1"));
 
     QCOMPARE(a.setNum(-123), QByteArray("-123"));
-    QCOMPARE(a.setNum(0x123,16), QByteArray("123"));
-    QCOMPARE(a.setNum((short)123), QByteArray("123"));
+    QCOMPARE(a.setNum(0x123, 16), QByteArray("123"));
+    QCOMPARE(a.setNum(short(123)), QByteArray("123"));
 
     QCOMPARE(a.setNum(1.23), QByteArray("1.23"));
     QCOMPARE(a.setNum(1.234567), QByteArray("1.23457"));