Index: src/OFString.m
==================================================================
--- src/OFString.m
+++ src/OFString.m
@@ -2380,10 +2380,13 @@
 				base = 8;
 
 			UTF8String++;
 		}
 	}
+
+	if (base == 0)
+		base = 10;
 
 	while (*UTF8String != '\0') {
 		unsigned char c = of_ascii_toupper(*UTF8String++);
 
 		if (c >= '0' && c <= '9')
@@ -2452,10 +2455,13 @@
 				base = 8;
 
 			UTF8String++;
 		}
 	}
+
+	if (base == 0)
+		base = 10;
 
 	while (*UTF8String != '\0') {
 		unsigned char c = of_ascii_toupper(*UTF8String++);
 
 		if (c >= '0' && c <= '9')

Index: tests/OFStringTests.m
==================================================================
--- tests/OFStringTests.m
+++ tests/OFStringTests.m
@@ -1081,10 +1081,11 @@
 	    C(@"\r\n+123  ").longLongValue == 123 &&
 	    C(@"-500\t").longLongValue == -500 &&
 	    [C(@"-0x10\t") longLongValueWithBase: 0] == -0x10 &&
 	    C(@"\t\t\r\n").longLongValue == 0 &&
 	    [C(@"123f") longLongValueWithBase: 16] == 0x123f &&
+	    [C(@"-1234") longLongValueWithBase: 0] == -1234 &&
 	    [C(@"\t\n0xABcd\r") longLongValueWithBase: 0] == 0xABCD &&
 	    [C(@"1234567") longLongValueWithBase: 8] == 01234567 &&
 	    [C(@"\r\n0123") longLongValueWithBase: 0] == 0123 &&
 	    [C(@"765\t") longLongValueWithBase: 8] == 0765 &&
 	    [C(@"\t\t\r\n") longLongValueWithBase: 8] == 0)
@@ -1092,10 +1093,11 @@
 	TEST(@"-[unsignedLongLongValue]",
 	    C(@"1234").unsignedLongLongValue == 1234 &&
 	    C(@"\r\n+123  ").unsignedLongLongValue == 123 &&
 	    C(@"\t\t\r\n").unsignedLongLongValue == 0 &&
 	    [C(@"123f") unsignedLongLongValueWithBase: 16] == 0x123f &&
+	    [C(@"1234") unsignedLongLongValueWithBase: 0] == 1234 &&
 	    [C(@"\t\n0xABcd\r") unsignedLongLongValueWithBase: 0] == 0xABCD &&
 	    [C(@"1234567") unsignedLongLongValueWithBase: 8] == 01234567 &&
 	    [C(@"\r\n0123") unsignedLongLongValueWithBase: 0] == 0123 &&
 	    [C(@"765\t") unsignedLongLongValueWithBase: 8] == 0765 &&
 	    [C(@"\t\t\r\n") unsignedLongLongValueWithBase: 8] == 0)